US3635603A

US3635603A - Rpm regulator for fuel injection pumps

Info

Publication number: US3635603A
Application number: US17199A
Authority: US
Inventors: Franz Eheim
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 1969-03-14
Filing date: 1970-03-06
Publication date: 1972-01-18
Anticipated expiration: 1989-01-18
Also published as: DE1912919A1; AT294494B; FR2038982A5; GB1294589A; JPS5248253B1

Abstract

In an r.p.m. regulator for fuel injection pumps, the adaptation of full load fuel quantities to the maximum quantities combustible in a smokefree manner is effected by the r.p.m.dependent pressure of a regulator fluid against the force of an adapter spring. The said adaptation does not interfere with the r.p.m. regulation proper.

Description

t n e t a P s e t a t against the force of an adapter spring. The said adaptation does not interfere with the rpm. regulation proper.

.imum quantities comcted by the r.p.m.-de-

ABSTMMZT In an rpm. regulator for fuel injection pumps, the adaptation lReflerences Cited UNITED STATES PATENTS Chandler............................ Dreisin Kleeberger Kemp 6 Claims, 11 Drawing Figure Primary ExaminerWi1liam L. Freeh Assistant Examiner-John J. Vrablik Att0rneyEdwin E. Greigg of full load fuel quantities to the max bustible in a smokefree manner is effe pendent pressure of a regulator fluid tliittlwlVhllll I t t i i e F .417/282, 417/289, 417/294 ....F04b 49/00, F0413 7/04 RPM REGULATOR FOR FUEL INJECTION PUMPS BACKGROUND OF THE INVENTION This invention relates to an r.p.m. regulator for fuel injection pumps associated with internal combustion engines and is of the type that has at least one intermediate lever which, on the one hand, is connected to and displaced by an r.p.m.- responsive device against an arbitrarily adjustable regulator spring and, on the other hand, is connected to and displaces a fuel quantity control member of the fuel injection pump. The travelling path of the fuel quantity control member in the direction of increasing fuel quantities is limited by an abutment member thus determining the maximum fuel quantities delivered by the fuel injection pump. The abutment member is displaceable by an r.p.m.-responsive means against the force of an adapter spring.

In a known r.p.m. regulator of the aforenoted type (such as disclosed, for example, in German Pat. No. 1,287,852), the r.p.m.-responsive device (a centrifugal governor) first compresses the adapter spring and thereafter affects the regulator spring. The adapter spring has a relatively flat spring characteristic, because it has to be effective over the entire r.p.m. range. The regulator spring, on the contrary (although being compressed only after compressing the adapter spring), has a steep spring characteristic to obtain a small p range (i.e., a favorable grade of nonuniformity). ln known governor structures (such as described in German Pat. No. 1,011,223), the regulator spring is effective not only for the terminal r.p.m., but also over the entire r.p.m. range as the driver changes the preload thereon. in known r.p.m. regulator structures, the adapter spring unavoidably interferes with the cooperation between the r.p.maesponsive device and the regulator spring. Such interference is disadvantageous in view of the strict requirements concerning the matching of the delivery characteristics of the fuel injection pump with the torque characteristics of the engine. The adapter spring should merely serve to coordinate the fuel quantities delivered by the fuel injection pump under full-load conditions of the engine with those r.p.m.-dependent maximum fuel quantities which are capable of smokefree combustion in the engine. It is desirable that during such operation of the adapter spring, the characteristics of the regulator spring remain unaffected.

R.p.m. regulators of the aforenoted type are known (as disclosed, for example, in US. Pat. No. 2,986,291) in which the abutment, determining the maximum fuel quantities, is shifted by hydraulic means into a position in which the fuel injection pump delivers an additional fuel quantity. Said hydraulic means serve for operating tractor-drawn implements. The said shift, however, occurs only subsequent to an arbitrary actuation of the implements, thus placing an additional load on the engine.

OBJECT AND SUMMARY OF THE INVENTION It is an object of the invention to provide an improved r.p.m. regulator for fuel injection pumps, wherein the aforenoted coordination controlled by r.p.m.-dependent means is independent of the r.p.m. regulation proper.

Briefly stated, according to the invention, said r.p.m.-dependent means is formed of a regulator fluid, the pressure of which augments as the r.p.m. increases and the displacement of the abutment is effected by said fluid independently of the position of the r.p.m.-responsive device.

The invention will be better understood as well as further objects and advantages will become more apparent from the ensuing detailed specification of a preferred, although exemplary embodiment of the invention taken in conjunction with the sole FIGURE which shows the embodiment diagrammatically and in longitudinal section.

DESCRIPTION OF THE PREFERRED EMBODIMENT In an only partially shown housing 1 ofa fuel injection pump there is provided a cylinder bore 2 in which there is disposed a pump piston 3. By means not shown, the latter is reciprocated against the force of a return spring at and is also caused to execute a rotary motion about its axis. During the return strokes of piston 3 and while it dwells in its lower dead center, the pump work chamber 2a forming part of cylinder 2, is supplied with fuel through longitudinal grooves 5 provided in the outer face of the piston 3 and through a bore 6 provided in the housing 1 and communicating with a suction chamber 7. As soon as the piston 3 has executed a predetermined portion of its pressure stroke and has rotated accordingly, the bore 6 is closed by the wall of piston 3. As a result, the fuel which is present in the pump work chamber 2a is, as the pressure stroke continues, forced through an axial channel 3 provided in the pump piston, a radial bore 8' and a longitudinal distributor groove 9 provided in the outer face of the pump piston, to one of a plurality of pressure conduits 10 (only one shown) which lead to the internal combustion engine, not shown.

The pump piston 3 is surrounded by a slidable control sleeve 12 which, during the pressure strokes of piston 3, is adapted to open a radial bore 13 provided in piston 3 and communicating with the axial bore 8, thus determining the fuel quantities delivered to the engine by the fuel injection pump. As the radial bore 13 emerges from sleeve 12 and thus opens, the fuel, as the pressure stroke of the piston 3 proceeds, flows into the suction chamber 7 through

bypass

8, 13 instead of into one of the pressure conduits 10.

The control sleeve 12 is displaceable by means of an intermediate lever 14 which is pivotable about a pin 15 affixed eccentrically to a shaft 16 held in the housing 1. As the shaft 16 is turned, the lateral position of the pin 15 is changed. The lever 14 is connected to and displaceable against the force of a regulator spring 18 by an r.p.m.-responsive device formed as a centrifugal governor generally indicated at 17. It includes weights 20 pivotally attached to a carrier 19 which, in turn, is driven with the r.p.m. of the fuel injection pump. As the weights 20 move outwardly in response to the increasing r.p.m. a governor sleeve 21 is displaced exerting a force on the lever 14. The preload of the regulator spring 18 resisting the aforenoted displacement of governor sleeve 21 is arbitrarily adjustable by means ofa rod 22. At one end, the lever 14 carries a spherical head 23 which engages a complemental depression 24 provided in the control sleeve 12.

The fuel quantities delivered by the fuel injection pump during each pressure stroke of piston 3 increase as the control sleeve 12 is shifted upwardly, because the radial bore 13 and thus the

bypass

8, 13 is opened at a correspondingly later moment. The uppermost position of the control sleeve 12 determining the maximum fuel quantity delivery is determined by an abutment 25 (full-load abutment) cooperating with the terminus of lever 1% remote from the spherical head 23. Said fullload abutment 25 is formed by one leg of a bellcrank lever 26 which is pivotable about a pin 27 affixed eccentrically to a shaft 28 held in the housing 1. As the shaft 23 is turned, the lateral position of the pin 27 is changed. The other leg of the bellcrank lever 26 terminates in a follower head 29 which is in contact with a cam track 30 provided in the outer face of a plunger 31.

The plunger 31 is axially displaceably held in a housing 33 which is affixed to the pump housing 1 and is in communication therewith.

The fuel present in the suction chamber 7 is admitted into a chamber 33a through an oblique bore 3 1 provided in the plunger 31. The fluid pressure in the chamber 33a displaces the plunger 31 to a greater or lesser extent against the force of a starting spring 35 and an adapter spring 36. The latter is disposed within a hollow piston 37 which is engaged by the plunger 31 as soon as the soft starting spring 35, disposed in a blind bore of plunger 31, is compressedl. Only thereafter will, upon further increase of the pressure in suction chamber 7 (and thus in chamber 331:), the plunger 31 displace the hollow piston 37 and thus compress the adapter spring 36. The provision of a relatively weak starting spring 35 in addition to the adapter spring 36 serves to maintain the working capacity of the r.p.m. regulator at a high level and is thus not limited by a range of starting r.p.m.s. With the aforedescribed arrangement of

springs

35 and 36 it is further achieved that the regulating force is no longer affected by the force of the starting spring which has been a drawback in known r.p.m. regulators, particularly in the idling r.p.m. range in which the regulator spring is only slightly compressed.

The spaces accommodating the

springs

35 and 36 are maintained depressurized through a channel 38 communicating with a tank 43. The initial and terminal positions of the

pistons

31 and 37 are determined by the

adjustable abutments

39 and 40 held in the housing 33.

The suction chamber 7 is supplied with fuel by a delivery pump 42 drawing fuel from the tank 43. The pressure in the suction chamber 7 is controlled in an r.p.m.-dependent, known manner by means of a pressure control valve 44 so that an increase of the r.p.m. causes an increase of the pressure in the suction chamber 7.

As a function of the r.p.m.-dependent linear position of plunger 31, the angular position of the bellcrank lever 26 is changed by virtue of the cam track 30. As a result, the position of the full-load abutment 25 is also changed. The cam track 30 is shaped in such a manner that the injected maximum fuel quantities determined by the full-load abutment 25 equal the maximum fuel quantities which at the given r.p.m. are capable of smokefree combustion.

By means of the eccentric pins and 27, the r.p.m. regulator may be adjusted in a desired manner.

It is thus seen that the coordination of the full-load fuel quantities with those still combustible in a smokefree manner and the cutoff of additional fuel quantities required for the starting of the engine are effected in such a manner that the working capacity of the r.p.m. regulator itself is not limited and that the regulation proper is not interfered with.

lclaim:

1. In an r.p.m. regulator for a fuel injection pump associated with an internal combustion engine and including a reciprocating pump piston, the improvement comprising,

A. a control sleeve surrounding said pump piston and axially slidable thereon to control the fuel quantities delivered by said pump piston,

B. a pivot,

C. an intermediate lever secured to said pivot for swinging movement thereabout, said intermediate lever being connected to said control sleeve at a location spaced from said pivot,

D. an r.p.m.-responsive device connected to said intermediate lever at a location spaced from said pivot for causing axial movement of said control sleeve as a function of the engine r.p.m.

E. a movable abutment cooperating with said intermediate lever for limiting the swinging motion thereof in a direction opposite to that caused by said r.p.m.-responsive device during an increase in r.p.m.; the position of said abutment determining the end of injection during each pressure stroke of said pump piston,

F. means for displacing said movable abutment in response to changes in the engine r.p.m., said last-named means including i. an adapter spring and 2. a regulating fluid of r.p.m.-dependent pressure opposing the force of said adapter spring and affecting said movable abutment.

2. An improvement as defined in claim 1, including A. a starting spring opposing, together with said adapter spring, the force of said r.p.m.-dependent pressure, said starting spring is weaker than said adapter spring and B. means for ensuring compression of said starting spring prior to adapter spring when said means exposed to an r.p.m.-dependent pressure is displaced against the force of said springs.

3. An improvement as defined in claim I, wherein said means for dis lacing said movable abutment includes A. a linear y movable plunger exposed at one side to the force of said adapter spring and, at the other side, to the r.p.m.-dependent pressure of said regulating fluid,

B. a cam track of predetermined curvature integral with said plunger and extending in the directions of its motion and C. means cooperating with said cam track and said movable abutment to cause displacement of the latter as a function of the shape of said cam track upon movement of said plunger.

4. An improvement as defined in claim 3, including additional adjustable abutment means to vary the extreme posi tions of said plunger.

5. An improvement as defined in claim 3, wherein said means cooperating with said cam track and said movable abutment includes a bellcrank lever pivotable about stationary pin means and formed of A. a first leg constituting said movable abutment and B. a second leg constituting a follower engaging said cam track.

6. A improvement as defined in claim 5, wherein said pin means is laterally adjustable to vary the position of the axis of rotation of said bellcrank lever.

Claims

1. In an r.p.m. regulator for a fuel injection pump associated with an internal combustion engine and including a reciprocating pump piston, the improvement comprising, A. a control sleeve surrounding said pump piston and axially slidable thereon to control the fuel quantities delivered by said pump piston, B. a pivot, C. an intermediate lever secured to said pivot for swinging movement thereabout, said intermediate lever being connected to said control sleeve at a location spaced from said pivot, D. an r.p.m.-responsive device connected to said intermediate lever at a location spaced from said pivot for causing axial movement of said control sleeve as a function of the engine r.p.m. E. a movable abutment cooperating with said intermediate lever for limiting the swinging motion thereof in a direCtion opposite to that caused by said r.p.m.-responsive device during an increase in r.p.m.; the position of said abutment determining the end of injection during each pressure stroke of said pump piston, F. means for displacing said movable abutment in response to changes in the engine r.p.m., said last-named means including 1. an adapter spring and 2. a regulating fluid of r.p.m.-dependent pressure opposing the force of said adapter spring and affecting said movable abutment.

2. a regulating fluid of r.p.m.-dependent pressure opposing the force of said adapter spring and affecting said movable abutment.

3. An improvement as defined in claim 1, wherein said means for displacing said movable abutment includes A. a linearly movable plunger exposed at one side to the force of said adapter spring and, at the other side, to the r.p.m.-dependent pressure of said regulating fluid, B. a cam track of predetermined curvature integral with said plunger and extending in the directions of its motion and C. means cooperating with said cam track and said movable abutment to cause displacement of the latter as a function of the shape of said cam track upon movement of said plunger.

4. An improvement as defined in claim 3, including additional adjustable abutment means to vary the extreme positions of said plunger.