GB2043296A - Speed governors for fuel injection type internal combustion engines - Google Patents

Abstract

A speed governor for vehicle diesel engines is proposed, in which the idling speed can be maintained at least approximately constant even when the engine is cold or when loaded by additional loads. The governor (1) includes a servo operated idling correction device (56) having a correction adjusting member (55) which varies the stressing force of the idle running spring (52). Preferably the vacuum pump 63 in the brake system of the vehicle, provides the servo output force. A control device (62) operates in dependence upon at least one variable (T, t, Z) influencing the idling performance of the engine so that the idling speed initially set for the hot, non-loaded engine by the idle running spring (52) is maintained at least approximately constant under changing idling conditions or loads. <IMAGE>

Description

SPECIFICATION Speed governors for fuel injection type internal combustion engines The invention relates to speed governors for fuel injection type internal combustion engines, such as a centrifugal speed governor for a fuel invention pump for a vehicle diesel engine.

A centrifugal speed governor is described in published German Patent specification (Offenlegungsschrift) No. 2,644,994, in which the initial stressing force of an idling running spring is increased when the engine is cold by means of a thermally controlled idling correction device, in order to ensure smooth running of the engine. A thermally responsive correction adjusting member is heated by a heater connected to the electrical control circuit and its "on" period, required only during warming-up of the engine, is limited by a temperature-dependent resistor, preferably in the form of a cold conductor (PTC resistor), incorporated in the electrical circuit of the heater.This device has the disadvantage that considerable forces have to be applied by the correction adjusting member, since the idle running spring is already abutting under initial stressing force against an adjustable abutment for the purpose of fixing the idling speed. Moreover, the idling speed cannot be rapidly adapted to changing loads on the engine by means of a device of this kind, since the device operates relatively slowly and sluggishly.

The invention resides in a speed governor for a fuel injection type internal combustion engine, comprising a governor member which is adjusted in position in dependence upon engine speed, the adjusting movements of the governor member being transmitted to the fuel delivery quantity adjusting member of the injection pump by way of at least one intermediate lever and being effected within an idling travel of the governor member against the force of an idle running spring, and also comprising an idling correction device having a correction adjusting member which is actuable by an auxiliary force, and which influences the idling governing, the imposition of the auxiliary force on the correction adjusting member being controlled by a control element of a control device in dependence upon at least one operating variable of the engine.

The speed governor, in accordance with the invention, has the advantage that the adjusting member can also overcome larger opposing forces by virtue of the auxiliary force to which the correction adjusting member is subjected in dependence upon at least one operating variable. Furthermore, the adjusting member can act, at an optional point advantageous with respect to the installation space, upon one of the parts of the governor or injection pump which are adjustable or movable for the purpose of controlling the idling position of the fuel delivery quantity regulating member, thus providing a considerable amount of freedom with respect to the arrangement of the idling correction device.A further advantage is that the auxiliary force can also be applied outside the warming-up time of the engine by simple switching means for the purpose of actuating the adjusting member if, for example, additional loads (auxiliary drives, air-conditioning system) are jointly driven by and are switched on whilst the engine is idling, so that smooth running of the engine is also achieved in these cases.

In a speed governor in which the initial force of the idle running spring is variable by the correction adjusting member acting upon an abutment for the idle running spring, the abutment for the basic setting and variation of the initial force of the idle running spring is, in a particularly advantageous manner, constructed by a part of the actuating element of the correction adjusting member, thus resulting in a simple construction.

Preferably the correction adjusting member has a housing which is screwed into the governor housing so as to be adjustable for the basic setting of the idling speed and is secured in position. Thus it is possible subsequently to adjust the idling speed externally without interfering in the governor. This fulfils an important demand on a modern certifugal speed governor for vehicle diesel engines that the setting member should be externally and freely accessible for the purpose of varying the idling speed. This subsequent adjustment of the idling speed is necessary, since, even in the same types of vehicles, the frictional resistances of the engine and thus the idling performance differ and smooth idling of the engine has to be ensured by correcting the idling setting.

This demand may also be fulfilled in another embodiment in which the abutment serves for varying the initial force of the idle running spring and is arranged on a support pin which is biassed to one extreme position by means of a spring and which is guided in a guide member and is displaceable into its other extreme position against the force of the last-mentioned spring by an actuating element of the correction adjusting member.Furthermore, in the speed governor in accordance with this other embodiment, the abutment for the idle running spring may be biassed when the engine is stationary by a support pin biassed to an extreme position by a spring, this having the advantage that, when starting the engine and if the auxiliary force possibly builds up slowly, an increase in the delivery quantity is effected to increase the idling speed and is then reduced more or less rapidly to the normal idling delivery quantity according to the operating state of the engine, so that a substantially constant idling speed is achieved.

Although hydraulic or electro-magnetic means can be used as the auxiliary force, a pneumatic pressure medium, preferably the vacuum produced by a vacuum pump of the brake system of the engine, is preferably used as the auxiliary force owing to the fact that it has a low sensitivity to temperature and is rapidly available. The adjusting member may be diaphragm operated and advantageously a pressure chamber at one side of the diaphragm of the adjusting member is conectible either to a vacuum line subjected to vacuum by the vacuum pump, or to a chamber subjected to atmospheric pressure, by means of a valve member, which serves as the control element of the control device. Continuous influencing of the idling governing can be achieved.

It will be appreciated, the invention also includes variants in which the correction adjusting member does not act directly upon the idle running spring but act upons the governor linkage or acts directly upon the fuel delivery quantity regulating member of the fuel injection pump.

The invention is further described, by way of example, with reference to the drawings, in which Figure 1 is-a a simplified section through a first embodiment of speed governor; and Figure 2 is a fragmentary section through a second embodiment.

Referring to Figure 1, a fly-weight carrier 11 of a centrifugal speed governor, in the form of an idling and maximum speed governor, is secured to the camshaft 10 of a fuel injection pump (otherwise not illustrated) for a diesel internal combustion engine, fly-weights 12 being pivotally mounted on the fly-weight carrier 11. The fly-weights 12 have thrust arms 13 which act upon a governor sleeve 14 serving as a governor member to transmit the stroke of the sleeve, effected by the fly-weights 12, to a stud 16.

The stud 16 is articulated by means of a pivot pin 17 to a guide lever 18 which is pivotable on a hinge pin 21 which acts as a pivot and which is secured to the governor housing 19, the guide lever thus guiding the governor sleeve 14 during its stroke movements.

A shift lever 22 is also articulated to the stud 16 by the pivot pin 17 and to a lever-like setting member 25. The setting member 25 is secured to a lever shaft 26 which is mounted in the governor housing 19 to act as a pivot pin and which can be actuated by means of an operating lever 27 (shown by broken lines) located outside the governor housing 19. The shift lever 22 is connected by means of a bearing 28 to an intermediate lever 29 which acts as a regulating lever. One end of the lever 29 is articulated by means of a resiliently yieldable connecting link 31 to a regulating rod 32 serving as a fuel delivery quantity regulating member of the injection pump. The other end of the intermediate lever 29 is supported on a pivot bearing 33.

The pivot bearing 33 of the intermediate lever 29 is fixed in the axial direction of the governor sleeve 14 by a set screw 38 and, by turning the set screw 38, the pivot bearing 33 can be varied for basic adjustment of the full load position, determining the full load delivery quantity, of the regulating rod when, as is frequently desired by the engine manufacturer, the illustrated starting and full load positions of the operating lever 27 and thus of the setting member 25, are fixed by a non-adjustable full load stop 41 secured relative to the housing.

When the governor sleeve 14 has covered an amount of idling travel designated a, the stud 16 abuts against an adaptation spring capsule 42 which in the present instance acts as a stroke stop. The adaptation spring capsule 42 is screwed into a force trasmission lever 43. The purpose of the adaptation capsule is to reduce the maximum injected fuel quantity in the middle and upper speed range to ensure complete combustion and so reduce smoke emission. The transmission lever 43 is pivotabie about the hinge pin 21 and its free end 43a is pressed by a main governor spring 44 against a stop 45 secured relative to the housing.The initial stress of the main governor spring 44, acting as a maximum speed governing spring, is determined by the position in which the spring 44 is installed and can be adjusted by means of an abutment 46 in the form of a screw-threaded sleeve which is screwed into the governor housing 19. The screw-threaded sleeve 46 is secured in its adjusted position by means of a lock nut 47 and, like the stoke stop 42 and the set screw 38 of the pivot bearing 33 and an idling stop 48 in the form of a stop screw, is disposed in the governor housing 19 and is accessible only after removal of the sealed closure cover 49.

As will be further explained hereinafter, only an abutment 51a for an idle running spring 52 is arranged such that it can be adjusted externally of the governor for correction of the idling speed even when the cover 49 is sealed. This is particularly advantageous and is necessary to enable the idling speed adjustment to be adapted to the differing friction horsepowers of different engines. A head 51b of an actuating pin 51 is located within the governor housing 19 and carries the adjustable abutment 51a, formed by an annular groove, for one end 52a of an idling running spring 52. The latter is a leaf spring and abuts against the transmission lever 43 by way of a bracket 53 acting as a fixed support or abutment.The other end 52b of the spring 52 which is remote from the abutment 51a presses against a transverse pin 54 on the guide lever 18 and thus transmits its force to the governor sleeve 14.

The actuating pin 51 serves as an actuating element of a correction adjusting member 55, constituted by a diaphragm adjusting member, of an idling correction device 56. An adjusting diaphragm 57 is rigidly connected to the actuating pin 51 and acts as a movable wall to define a pressure chamber 58 in the housing 59 ofthe correction adjusting member 55.

The pressure chamber 58 is connected by way of a vacuum line 61 to a control device 62 whose control member, further described below with reference to Figure 2, connects the vacuum line 61 to a vacuum pump 63 of the brake system of the vehicle when an operating variable (further described hereinafter) of the engine has reached a corresponding value.

When the actuating pin 51 is in its illustrated starting position, the vacuum line 61 is connected by means of the control device 62 to a line 64 which leads to a chamber subjected to atmospheric pressure, preferably the air filter of the engine. The actuating pin 51 is held in this described starting position by the initial force of the idle running spring 52, provided that the engine is running under normal hotcondi- tions and the idling fuel delivery quantity corresponding to the idling performance is introduced by the regulating rod 32 by the preset initial force of the idle running spring 52. The corresponding position of the regulating rod 32 is designated L.

The housing 59 of the correction adjusting member 55 is screwed into the governor housing 19 by means of a screw-thread connection piece 59a and is secured in its fitted position by means of a nut 65.

The housing 59 is thereby adjustable externally for the basic setting of the idling speed, since, by turning the housing 59, the position of the abutment 51a is changed and thus the initial force of the idling running spring 52 is adjusted. The distance between the housing 59 of the adjusting member 55 and the head Sib of the actuating pin 51 which carries the abutment 51a is designated b. The additional initial travel for increasing the initial force of the idle running spring 52 is determined by the distance b which, when the load on the engine is correspondingly increased, shifts the position L of the regulating rod 32 by the predetermined amount towards the full load position V of the regulating rod.

Such an increase in the idling delivery quantity is necessary when the engine has not yet attained its operating temperature upon starting and, as a result of the increased frictional horsepower, a larger idling delivery quantity is required in order to maintain the given idling speed. The influence of this temperature T is indicated by a corresponding arrow on the control deivce 62. Since the warming-up phase is relatively short in many engines and is, for example, 20 to 90 seconds, the corresponding temperature control member can be replaced by a timedependent operating switching member whose function is designated by the symbol tat the arrow already designated Tin Figure 1. An increased idling performance is also demanded of the engine when additional loads are switched on.The corresponding additional load then has to be taken into account by a control member (not further described) upon actuating the control device 62 and is indicated by Z at the arrow already designated T and t Figure 2 shows a part of the preferred second embodiment in which the parts which correspond to the parts illustrated in a simplified form in Fgiure 1, and which act in the same way, are provided with the same reference numerals, slightly modified components being provided with an index mark.

The idling correction device designated 56' includes a diaphragm adjusting member 55' whose housing 59' is screwed into a screw-threaded sleeve 71 which is in turn screwed into the governor housing 19 and is secured in position by means of the nut 65.

A sleeve-like guide member 72 is secured in the screw-threaded sleeve 71 and accommodates a support pin 73 whose head 73a, extending into the governor housing 19, carries the abutment 73b, in the form of an annular groove, for one end 52a of the idle running spring 52. The force of a spring 74 maintains the support pin 73 in its illustrated starting position in which it is displaced to the right. Thus, the force of the spring 74 has to be larger than the initial force of the idle running spring 52, and, in this embodiment, the idle running spring 52 is initially stressed to control an increased idling delivery quantity when the support pin 73 is in its starting position.When the diaphragm adjusting member 55' is actuated by the vacuum, the support pin 73 is displaced to the left by the amount b until it abuts against the guide member 72 when the pressure chamber 58', located on the left of the adjusting diaphragm 57 in the present instance, is subjected to the vacuum of the vacuum pump 63 by the control device 62.

The vacuum pump 63 feeds a brake booster 76 of the brake system of the engine by way of a non-return valve 75 which is incorporated for safety reasons and, when the engine is under normal load and is at its operating temprature, the vacuum pump 63 is connected to the pressure chamber 58' of the diaphragr,l adjusting member 55' by way of a three port, two position valve 77, serving as a control element of the control device 62 and by way of the vacuum line 61.The force acting upon the adjusting diaphragm 57 as a result of the vacuum displaces an actuating stem 78 serving as an actuating member to the leR against the force of the spring 74 and thus presses the support pin 73 into the position (not illustrated) in which it abuts against the guide member 72 and in which the idle running spring 52 is subjected to an initial force which determines the normal idling speed. The control element 77 is illustrated in the position in which atmospheric pressure is admitted into the vacuum line 61 by way of the line 64.As is indicated by a corresponding arrow, the control element 77 is actuated in dependence upon the operating temperature T and/or predetermined "on" time t and/or in dependence upon the switching-on of an additional load and the imposition of the additional force Zthus required, by means of an actuating device 79, which takes the form of an actuating solenoid, a valve or a corresponding switching element. A pressure regulator 81, indicated by dash-dot lines, is incorporated in the vacuum line 61 between the multi-position valve 77 and the pressure chamber 58'.The vacuum which is fed to the pressure chamber 58 and which acts as an auxiliary force is continuously variable, if required, by the pressure regulator 81 likewise in dependence upon the said operating variable and/or further operating variables of the engine, whereby the initial force of the idle running spring 52 is continuously corrected in a corresponding manner.

During the governing-down movement of the force trasmission lever 43 (see also Figure 1) controlled by the governor sleeve 14, the idle running spring 52, which abuts by way of the bracket 53 against the transmission lever 43 pivotable about the bearing pin 21, effects a movement relative to the support pin 73 although, owing to the advantageous position of the support pin 73 approximately on a level with the bearing pin 21,this relative movement does not have a disadvantageous effect upon-the initial force of the idle running spring 52.

The mode of operation of the governor, constructed in accordance with the invention, as illustrated in Figures 1 and 2 will now be briefly described hereinafter insofar as it has not been described hitherto.

Referring to Figure 1, all the parts of the governor are shown in their normal positions upon starting, the setting member 25 being pivoted into the full load position in which the operating lever 27 abuts against the full load stop 41. the regulating rod 32 is in its maximum position designated max which determines the starting quantity. When the engine is started, the fly-weights 12 swing outwardly and the governor sleeve 14 covers its idle travel a and thereby pulls the regulating rod 32 into its full load position V by way of the intermediate lever 29. When the setting member 25 is then withdrawn into its idling position (not illustrated) in order to govern the idling speed, the setting member 25 pivots about the lever shaft 26 in a clockwise direction and abuts against the idling stop 48, and the regulating rod 32 assumes a position Lwhen the idling speed is reached.However, when the engine is cold, this normal position does not suffice to feed the engine with the delivery quantity needed to achieve idling performance. Thus, when the operating temperature T lies below a specific temperature threshold, the control device 62 connects the pressure chamber 58 to the vacuum pressure source 63, the abutment 51 a is displaced by the distance b, and the idle running spring 52 exerts an additional adjusting force upon the guide lever 18 way way of the transverse pin 54 to increase the idling delivery quantity. The guide lever 18 transmits this additional force to the governor sleeve 14, thus leading to correspondingly predetermined displacement of the regulating rod 32 from its normal idling position L in the direction towards the full load position V when the idling speed is uniform.With rising temperature, or after expiry of a predetermined period of time, or after the additional load has been switched off, the control device 62 reconnects the pressure chamber 58 to the line 64 subjected to atmospheric pressure, and the abutment51a ofthe idle running spring 52 returnsto its position illustrated in Figure 1. The regulating rod 32 is then again in its idling position L established for normal operation.

The converse mode of operation of the second embodiment illustrated in Figure 2 has already been described with reference to Figure 2 and, in the case of a brake system of the engine operating with compressed air, the diaphragm adjusting members 55 and 55' can also be actuated to admit pressure, the pressure chamber 58 of Figure 1 and the pressure chamber 58' of Figure 2 then being arranged at the opposite side of the adjusting diaphragm 57 respectively and, controlled by the control device 62, can be supplied with compressed air by way of a control line corresponding to the vacuum line 61.

If an electro-magnetic auxiliary force is used for the same purpose, the diaphragm adjusting members 55 and 55' are replaced by a corresponding adjusting solenoid, and the control device 62 operates with electrical switching or control elements.

Claims (14)

1. A speed governor for a fuel injection type internal combustion engine, comprising a governor member which is adjusted in position in dependence upon engine speed, the adjusting movements of the governor member being transmitted to the fuel delivery quantity adjusting member of the injection pump by way of at least one intermediate lever and being effected within an idling travel of the governor member against the force of an idle running spring, and also comprising an idling correction device having a correction adjusting member which is actuabie by an auxiliary force, and which influences the idling governing, the imposition of the auxiliary force on the correction adjusting member being controlled by a control element of a control device in dependence upon at least one operating variable of the engine.

2. A speed governor as claimed in claim 1, in which the initial force of the idle running spring is variable by the correction adjusting member which acts upon an abutment for the idle running spring.

3. A speed governor as claimed in claim 2, in which the abutment serves for the basic setting and varying of the initial force of the idle running spring and is constituted buy a part of the actuating element of the correction adjusting member.

4. A speed governor as claimed in claim 1,2 or 3, in which the correction adjusting member has a housing which is screwed into the governor housing so as to be adjustable for the basic setting of the idling speed and is secured in position.

5. A speed governor as claimed in claim 2, in which the abutment serves for varying the initial force of the idle running spring and is arranged on a support pin which is biassed to one extreme position by means of a spring and which is guided in a guide member and is displaceable into its other extreme position against the force of the last-mentioned spring by an actuating element of the correction adjusting member.

6. A speed governor as claimed in claim 5, in which the abutment for the idle running spring assumes a position displaced to increase the initial force of the idle running spring when the support pin is displaced to a position determined by the force of the spring.

7. A speed governor as claimed in claim 5 or 6, in which a screw-threaded sleeve which accommodates the guide member and mounts the correction adjusting member is screwed into the governor housing so as to be adjustable and fixable in position for the basic setting of the idling speed.

8. A speed governor as claimed in any preceding claim, in which the adjusting member is diaphragmoperated.

9. A speed governor as claimed in any preceding claim, in which the adjusting member is pneumaticaily operated.

10. A speed governor as claimed in claim 9, in which the adjusting member is operated from the vacuum produced by a vacuum pump of a brake system of a vehicle to which the engine is fitted.

11. A speed governor as claimed in claim 10, when appendentto claim 8, in which a pressure chamber at one side of the diaphragm of the adjusting member is connectible either to a vacuum line subjected to vacuum by the vacuum pump, orto a chamber subjected to atmospheric pressure, by means of a valve member, which serves as the control element of the control device.

12. A speed governor as claimed in claim 9,10 or 11, in which the pressure of the pressure medium fed to the correction adjusting member is continuously variable by a pressure regulator in dependence upon at least one operating variable of the engine.

13. A speed governor as claimed in any preceding claim, in which the governor member comprises a governor sleeve actuated by fly-weights.

14. A speed governor for a fuel injection type internal combustion engine, constructed and adapted to operate substantially as herein described with reference to and as illustrated in the drawings.