GB2179473A

GB2179473A - A centrifugal governor for internal combustion engines

Info

Publication number: GB2179473A
Application number: GB08619940A
Authority: GB
Inventors: Sieghart Maier
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 1985-08-16
Filing date: 1986-08-15
Publication date: 1987-03-04
Also published as: GB2179473B; GB8619940D0; DE3529448A1; JPS6245942A; DE3529448C2

Abstract

A centrifugal governor for an internal combustion engine has a flyweight adjuster (1) which acts by way of a swivel head (7), (by way of which a guide lever (16) and hence a quantity control member (21) are moved), on a thrust member (8) and hence on other control members, which act against the adjusting force of the flyweight adjustor at least from the point at which a certain speed or load is reached. The swivel head (7), thrust member (8) and guide lever (16) are articulated by means of a pivot pin (24) whereby the thrust member 8 engages squarely with the tensioning lever 9. <IMAGE>

Description

SPECIFICATION Centrifugal governor for an internal combustion engine The present invention relates to a centrifugal governor for an internal combustion engine.

In this type of centrifugal governor (for example Bosch variable-speed governor EP/RSV), flyweights act by way of bell-crank levers, usually with the interposition of an axial bearing and an adjusting sleeve, on a swivel head, to which a two-armed guide lever is linked and on which a further control element acts, such as an adaptation thrust member, on which, however, an arbitrarily alterable control force acts against the centrifugal force.

Each position of the swivel head corresponds to a particular quantity of fuel to be injected and furthermore corresponds to a situation of equilibrium between, on the one hand, speed-sensitive centrifugal force, that is, flyweight adjuster force, and, on the other hand, a governor spring force which is usually composed of the force of an arbitrarily alterable governor spring and of an adaptation spring effective once a particular speed has been reached. In order for the governor to function precisely, it is necessary that, on the one hand, governor positions corresponding to particular characteristics such as speed and load, and hence quantities of fuel to be injected, are repeated precisely, and that, on the other hand, the frictional forces are as low as possible and the time required to take up each governor position is as short as possible.

In known governors of this type, tilting or too much friction, and sometimes also twisting of the lever system, produces repetitive tolerances which, on the one hand, impair the accuracy of the governor and, on the other hand, lead to peculiarities such as unwanted adaptation. These tolerances are partly based on the inclined position of individual control elements, such as the swivel head, in relation to the direction of adjustment, which, instead of the desired line contact, results in pointwise contact and a spreading apart of the opposing faces. Twists in the lever linkage lead to increased friction in the bearings and also to a change in the position of the points of force transmission with the above-mentioned sequence of errors in fuel metering.

In one governor of this type (German Patent Specification No. 10 11 223), a further control element is provided in the form of a tensioning lever against which the governor spring abuts and against which, either directly or by way of an adaptation element, the side of the swivel head remote from the flyweight adjuster pushes. This tensioning lever is mounted in the housing at its end remote from the above-mentioned contact point with the swivel head. The governor spring can be arbitrarily altered, whereby the position of the guide lever determining the quantity of fuel to be injected is dependent upon the respective position of the tensioning lever which is in turn determined by the equilibrium between the forces acting on the swivel head, namely, on the one hand, the force of the centrifugal adjuster and, on the other hand, the force of the governor spring.Furthermore, at the point at which the swivel head meets the tensioning lever, a resilient adaptation thrust member is provided for adapting the metered fuel to the injected fuel quantity which is combusted without smoke, the spring of which adaptation thrust member yields when the adjusting force reaches a certain level, so that a superimposition of the governor spring forces occurs.

As soon as a unilateral load occurs, which may be caused, for example, by the thrust fingers of the flyweights, unilateral eccentric supports are produced during force transmission, as the swivel head is rigidly mounted in the guide lever by way of axle ends disposed transversely to the direction of adjustment.

The twisting of the guide lever rotates the swivel head out of the direction of adjustment, as a result of which one of its lateral edges meets the tensioning lever too soon and, in certain circumstances, causes the tensioning lever to rotate such that, as a result of the unilateral contacts, changes in the regulating values occur sooner than desired during force transmission. In order to avoid this, the unwanted inclination of the thrust member due to the starting spring is compensated for by intentionally offsetting the guide lever, which requires additional manufacturing outlay.

In another known centrifugal governor (Austrian Patent Specification No. 220 429), the swivel head is suspended semicardanically between the adjusting sleeve of the flyweight adjuster and the guide lever, with the disadvantage of relatively uneven guiding and of the bell-crank levers of the flyweights being rigidly coupled such that they affect one another.

In accordance with the present invention there is provided a centrifugal governor for an internal combustion engine, said governor comprising a swivel head displaceable against a return force by a flyweight adjuster driven at a rotational speed synchronous to that of the engine, the side of the swivel head remote from the flyweight adjuster co-operating in the direction of adjustment with a further control member which acts against the adjusting force of the flyweight adjuster at least once a certain speed or load has been reached, and a guide lever which is at least indirectly connected to a delivery quantity control member and which has two ends extending in the same direction and between which ends the swivel head is mounted which can be rotated about an axis of rotation running through the bearings in the guide lever transversely to the direction of adjustment, wherein a pivot pin is provided in the swivel head in the middle be tween the guide lever ends and perpendicular to the transverse axis and to the direction of adjustment, on which pivot pin a thrust member is articulated for the purposes of transmitting force to the other control member.

Such a centrifugal governor has the advantage that the correcting variables are transmitted in the direction of adjustment by way of the swivel head to the further control members, and that the pivoting of the thrust member by way of the pivot pin prevents angular displacements of the swivel head relative to the direction of adjustment from acting as travel errors. The distance between the forcetransmitting pivot pin and the face of the thrust piece facing, and co-operating with, the other control members, remains the same.

According to an advantageous embodiment of the invention, a further control element is provided in the form of a tensioning lever with a preferably arbitrarily alterable governor spring acting thereon, and/or in the form of an adaptation thrust member by means of which the quantity of fuel injected can be adapted, once a particular speed has been reached, to the quantity of fuel which can be combusted without smoke, by rendering an adaptation spring operative or inoperative.

In both embodiments, if the swivel head is tilted or the guide lever twisted, the thrust member prevents the other control members causing travel displacements which could impair governing.

According to a further embodiment of the invention, the swivel head is provided with a recess which is open towards the thrust member for accommodating a bearing eye on the thrust member and is penetrated by the pivot pin, or, in accordance with another advantageous embodiment of the invention, the thrust member is provided with a U-shaped cross-section in the sectional plane of the direction of adjustment and the pivot pin direction, and engages with play over the swivel member in the direction of adjustment, the pivot pin penetrating both these members.

The semicardanic suspension of the thrust member on the swivel head by way of the pivot pin ensures, in a manner advantageous from the point of view of manufacturing, that force transmission in the direction of adjustment is given without the occurrence of additional travel errors, even if the swivel head is tilted.

According to a further embodiment of the invention, a mounting is provided between the swivel head and the guide lever arms in the form of a bow surrounding the swivel head and having a U-shaped cross-section relative to the sectional plane determined by the direction of the pivot pin axis and the axis of rotation, the ends of which bow form bearings with the free ends of the guide lever, and the central part of which bow is penetrated by the pivot pin. The bearings can be in the form of journals and associated bores, which are provided at the ends of either the bow or the guide lever. Together with the thrust member articulated on the pivot pin, a cardanic transmission of force is produced between the swivel head, guide lever and other control member so that, even if the guide lever is twisted, no disadvantageous distortion forces occur, which would above all increase friction.

By way of example only, specific embodiments of the present invention will now be described, with reference to the accompanying drawings, in which: Figure 1 shows a centrifugal governor; Figure 2 shows a section through the articulated region between the swivel head and the guide lever of a first embodiment of governor, alone the line ll-ll in Fig. 3; Figure 3 a section along the line Ill-Ill in Fig.

2; Figure 4 is a view of the swivel head in the direction of the arrow IV; Figure 5 is a part section through the swivel head along the line V-V in Fig. 3; Figure 6 is a variant of the first embodiment illustrated in Figs. 2 to 5, and corresponding to Fig. 3; Figure 7 is a section through the articulated region of a second embodiment of governor, along the line VII-VII in Fig. 8; Figure 8 is a section along the line VIII-VIII in Fig. 7; and Figure 9 is a section through the thrust member along the line IX-IX in Fig. 7.

In a first embodiment of speed governor, shown in simplified form in Fig. 1, a flyweight adjuster 1 is driven by a drive shaft 2-which is usually the camshaft of the injection pump-at a speed synchronous with that of the engine. Flyweights 3 act by way of bell-crank lever 4 on an adjusting sleeve 5 which is frictionally connected by way of an axial bearing 6 to a swivel head 7 in the direction of an adjustment I. The adjusting force, which can be generated by the flyweights 3, corresponds to the drive speed.

On its side remote from the flyweight adjuster 1, the swivel head 7 is provided with a thrust member 8, which acts on a tensioning lever 9, which is pivotable about an axis 10.

The tensioning lever 9 is biassed by the force of a governor spring 11 against the adjusting force of the flyweight adjuster 1, the prestressing of which governor spring can be adjusted arbitrarily by way of an adjusting lever 12. The thrust member 8 acts by way of an adaptation spring 13 on the tensioning lever 9, wherein the forces of the springs 11 and 13 are superimposed on one another for regulation. The initial position of the tensioning lever 9 is determined by an adjustable stop 14.

A guide lever 16 having two parallel mounting arms at one end thereof is pivoted at pivotal points 15 by the swivel head 7, only one arm of the lever being visible and the lever being pivotably mounted on the axis 10 at its end remote from the pivotal points 15.

The guide lever 16 carries a swivel axis 17 of a governor lever 18 which is provided at one end with a fixed hinged bearing 19 and at the other end is biased by a starting spring 20.

This governor lever 18 is connected to a member 21 for controlling the quantity of injected fuel, for example a control rod of the fuel injection pump.

This centrifugal governor operates as follows: To start, the governor lever 18 is swung to the left by the starting spring 20 and hence the quantity control member 21 and the swivel head 7 are also moved to the left. This position corresponds to a large quantity of injected fuel as required for starting the internal combustion engine. As soon as the engine has started and the adjusting lever 12 is still in its initial position for idle speed, the flyweights 3 move the swivel head 7 to the right, whereby, as a result of the slight prestressing of the spring 11, both the tensioning lever 9 and the guide lever 16 are swung to the right. Towards the end of its swing position, the tensioning lever 9 meets an idling spring 22 disposed in the housing, whose force, in equilibrium with the centrifugal forces, meters a sufficient quantity of fuel to maintain the idling speed.As soon as the adjusting lever 12 is moved into the position shown, in which the governor spring 11 is strongly prestressed, the disturbed equilibrium causes the tensioning lever 9 and, by way of the thrust member 8, the swivel head 7 and hence the guide lever 16 to be pivoted to the left, as a result of which the quantity control member 21 is moved by way of the swing axis 1 7 to the left into a position for a large quantity of injected fuel. The flyweight forces, which increase with increasing speed, then act against this spring force until a state of equilibrium has been achieved.When a certain speed has been reached, that is when a certain flyweight force has been achieved, the adaptation spring 13 yields, as a result of which the quantity of fuel injected changes in relation to the position of the tensioning lever 9 or the prestressing of the governor spring 11. With this adaptation, the actual quantity of fuel injected is matched to the quantity of fuel which can be combusted without smoke by the engine.

The invention relates to the articulated region between the swivel head 7 with the thrust member 8 and guide lever 16, and is shown in two embodiments, namely in a first embodiment in Figs. 2 to 6 and in a second embodiment in Figs. 7 to 9, whereby Fig. 6 shows a variant of the first embodiment.

As can be seen from Figs. 2 to 5, in the first embodiment, the thrust member 8 is in the form of a plate having an approximately Tshaped extension and is guided between two flat projections 23 on the swivel head 7 and is hinged by way of a pivot pin 24 which penetrates the flat projections 23 and the thrust member 8. The swivel head 7 is provided in the direction of adjustment as seen from the flyweight adjuster side with a central blind bore 25 into which a guide rod, for example, a shaft stub, projects from the drive side. If, for example, the swivel head 7 is slightly rotated about the pivot pin 24, for example by tilting from the flyweight adjuster side, the thrust member 8 can turn such that the end face 26 facing the tensioning lever always remains perpendicular to the direction of adjustment I.

In addition, a bow 27 is articulated by the pivot pin 24, the ends of which bow engage over part of the thrust member 8 and swivel head 7 and in which bearing openings 29 are provided, into which journals 30 engage. One journal 30 is secured in each of the two arms 31 of the guide lever 16.

In the variant shown in Fig. 6, there is a reversal of these bearings such that the journals 30' are secured to the bow ends 28' and that, correspondingly, the bearing openings 29' are provided in the arm 31' of the guide lever.

While the first embodiment has largely cardanic properties, the second embodiment, which is simpler to manufacture, is only a semicardanic version.

As can be seen from Figs. 7 to 9, the swivel head 107 is provided with a central cross bore 33 which is crossed by the vertical bore 34 accommodating the pivot pin 124.

Two journals 35 are inserted into this cross bore 33, the free ends of which journals are mounted as axle ends in corresponding openings 129 in the guide lever arms 131. In this case, the thrust member 108 is U-shaped and surrounds the swivel head 107 such that it can be connected to it by means of the pivot pin, whereby the pivot pin 124 penetrates the swivel head 107 and the ends of the thrust member 108.

All the features in the description, claims and drawings can be essential for the invention either individually or in combination.

Claims

1. A centrifugal governor for an internal combustion engine, said governor comprising a swivel head displaceable against a return force by a flyweight adjuster driven at a rotational speed synchronous to that of the engine, the side of the swivel head remote from the flyweight adjuster co-operating in the direction of adjustment with a further control member which acts against the adjusting force of the flyweight adjuster at least once a certain speed or load has been reached, and a guide lever which is at least indirectly connected to a delivery quantity control member and which has two ends extending in the same direction and between which ends the swivel head is mounted which can be rotated about an axis of rotation running through the bearings in the guide lever transversely to the direction of adjustment, wherein a pivot pin is provided in the swivel head in the middle between the guide lever ends and perpendicular to the transverse axis and to the direction of adjustment, on which pivot pin a thrust member is articulated for the purposes of transmitting force to the other control member.

2. A centrifugal governor as claimed in claim 1, comprising a further control member in the form of a tensioning lever, which is biased by a governor spring.

3. A centrifugal governor as claimed in claim 1 or claim 2, wherein an adaptation thrust member having an adaptation spring serves as a further control member and can be rendered operative or inoperative once a certain speed has been reached.

4. A centrifugal governor as claimed in any of claims 1 to 3, wherein the swivel head is provided with a recess which is open towards the thrust member and which accommodates a bearing eye on the thrust member, which eye is penetrated by the pivot pin.

5. A centrifugal governor as claimed in any of claims 1 to 4, wherein the thrust member has a generally U-shaped cross-section in the sectional plane formed by the direction of adjustment and the direction of the pivot pin axis, and engages over the swivel member, and wherein the pivot pin penetrates said thrust member and said swivel member.

6. A centrifugal governor as claimed in any of the preceding claims, wherein the bearing between the ends of the guide lever and the swivel head is in the form of journals inserted in a transversely extending bore of the swivel head crossing the pivot pin, the free ends of which journals are mounted in openings in the guide lever ends serving as bearings.

7. A centrifugal governor as claimed in any of claims 1 to 5, wherein the bearing is in the form of a bow surrounding the swivel head and having a generally U-shaped cross-section in relation to the sectional plane formed by the direction of the pivot pin axis and the rotational axis, whose ends form bearings with the free ends of the guide lever and whose central part is articulated by the pivot pin.

8. A centrifugal governor as claimed in claim 7, wherein the bearings are journals disposed on the ends of the guide lever, which journals are mounted in openings associated therewith in the free ends of the bow.

9. A centrifugal governor as claimed in claim 7, wherein the bearings are journals disposed on the free ends of the bow which project into openings in the ends of the guide lever associated therewith.

10. A centrifugal governor for an internal combustion engine, substantially as herein described, with reference to, and as illustrated in, Figs. 1 to 5, Figs. 1 to 5 as modified by Fig. 6, or Figs. 1 and 7 to 9 of the accompanying drawings.