Housing for fuel pump control assembly

A fuel assembly includes a main fuel pump housing from which extends a control rod into a compartment in a housing which also mounts a rotary actuator having a shaft which mounts link means located within the compartment and effecting movement of the aforesaid control rod. The housing includes a dividing wall through which the shaft extends and a fluid seal is provided about the shaft to prevent lubricant which may accumulate in the compartment flowing into a further compartment which contains the actuator.

This invention relates to a fuel pump assembly for supplying fuel to an 
internal combustion engine and comprising a first housing containing a 
plurality of injection pumps actuable in timed relationship to supply 
fuel, in use, to the combustion spaces of an associated engine, said 
injection pumps having a common control member movable to determine the 
amount of fuel supplied by the injection pumps, the assembly including a 
second housing which is secured to the first housing and which 
accommodates a rotary electromagnetic actuator, and the assembly also 
including means for operatively connecting the output shaft of the 
actuator with the control member. 
The first housing contains lubricant for the moving parts of the injection 
pump and it is desirable to prevent this lubricant reaching the actuator. 
It is also desirable that the means connecting the control member and the 
output shaft should be efficient as possible to minimise the electrical 
power required to effect movement of the control member. Moreover, from 
the servicing point of view it is desirable that the two housings should 
be easily separated and re-assembled. 
According to the invention in an assembly of the kind specified said second 
housing defines first and second compartments having a dividing wall 
therebetween, said control member extending into the first compartment, 
the actuator being located in the second compartment with the output shaft 
extending through said dividing wall, the axis of movement of said shaft 
being substantially at right angles to but offset from the axis of 
movement of the control member, said shaft mounting link means engageable 
with said control member and said dividing wall mounting a fluid seal 
member engaging with said shaft to prevent flow of lubricant between said 
compartments.

Referring to the drawings, the assembly comprises a first housing 10 and a 
second housing 11. The two housings are secured together by means of 
bolts. 
The housing 10 houses a plurality of individual fuel injection pumps 12 
each of which is of a wellknown design. The pumping plungers of the pumps 
12 are moved to displace fuel through respective outlets, by means of 
respective cams 13 mounted on a cam shaft 14. The cam shaft 14 is 
supported in the housing 10 by means of a bearing assembly 15 located in 
an end wall 16 of the housing, the cam shaft having a similar bearing at 
the opposite end of the housing and also intermediate bearings. At the 
opposite end of the housing to that which is shown, the cam shaft extends 
through an aperture and in use, is coupled to a drive coupling so that the 
cam shaft can be driven in timed relationship with the associated engine. 
Each injection pump is provided with a spring which effects movement of 
the respective plunger in the direction to draw fuel into the pumping 
chamber of the pump. The angular settings of the pumping plungers can be 
adjusted to control the amount of fuel which is supplied through the 
outlets at each injection stroke. For this purpose a control member 17 is 
provided and this extends the length of the pump. Forked coupling members 
18 are mounted on the control member and these engage with arms 19 
respectively which are coupled to the plungers. The control member 17 is 
movable axially to vary the angular setting of the plungers and in the 
particular example, movement of the control member 17 towards the right 
effects a reduction in the amount of fuel supplied by the injection pumps. 
Conveniently the control member 17 is of square section and is housed 
within a bearing bush 20 secured within the end wall 16 of the housing 10. 
The bush 20 also acts as an abutment for one end of a coiled compression 
spring 21, the other end of which engages a surface formed on a follower 
22 which is secured to the control member 17. The action of the spring 21 
is to move the control member 17 to the minimum or zero fuel position. 
The bearing assembly 15 comprises a tapered roller thrust race 23, the 
outer member of which is located within a sleeve 24, the sleeve having an 
integral flange 25 secured by studs 26 in the end wall 16 of the housing 
10. The studs are extended and serve to secure the two housings 10, 11 in 
face-to-face relationship. 
The housing 11 is constructed so as to define a first compartment 27, a 
second compartment 28, and a third compartment 29. As will be seen from 
FIG. 1, the wall of the housing 11 which is adjacent the wall 16 is 
provided with an aperture 30 through which the control member 17, the 
follower 22 and the spring 21 extend. Moreover, the aforesaid end wall of 
the housing 11 is recessed to accommodate the flange 25 and a fluid seal 
is formed about the periphery of the flange by a resilient "O" ring housed 
within a groove formed in the flange. 
The compartment 29 houses a speed transducer 31 and this includes a rotary 
shaft 32 carried on bearings 33, 34, the shaft mounting a toothed wheel 
35. An oil seal 36 is provided intermediate the bearing and the toothed 
wheel so that while the bearing 32 is lubricated by lubricant contained 
within the housing 10, the seal 36 prevents the lubricant flowing into the 
compartment 29. The bearing 34 is packed with grease during assembly. The 
transducer 31 incorporates a pole piece 37 which surrounds the wheel 35 
and like the wheel 35, is formed from magnetizable material. The magnetic 
circuit between the wheel 35 and the pole piece 37 is completed by a 
stator structure 38 which extends to adjacent the shaft 32. The stator 
structure mounts a pair of windings shown together at 39 and these are 
connected by suitable leads to exterior of the housing. The end of the 
shaft 32 adjacent the housing 10 is provided with a transverse slot 40 and 
engageable within this slot is a spring-loaded plunger 41 which is mounted 
within a bore formed in the cam shaft but eccentrically disposed relative 
to the axis of rotation thereof. Thus, as the cam shaft rotates rotary 
movement will also be imparted to the shaft 32 and by virtue of the 
toothed wheel and pole piece 37, an alternating current signal will be 
produced in the output winding, the frequency of the signal depending upon 
the speed of rotation of the cam shaft. 
Turning now to FIG. 2, the compartment 28 houses an electromagnetic 
actuator 42 and this comprises a rotor 43 and a stator 44. The rotor is 
mounted upon a shaft 45 and at its opposite ends, is carried by bearings 
46, 47. The axis of rotation of the shaft 45 is substantially at right 
angles to the axis of movement of the control member 17 and is laterally 
displaced relative thereto. The lower bearing 47 is mounted within an end 
plate 48 which forms the dividing wall between the compartments 27 and 28. 
The end plate has a flange portion which mounts an annular seal so as to 
establish a fluid-tight seal between the compartments 27 and 28. The 
bearing 46 is mounted within a housing part 49 which, together with a 
cover 51, defines a further compartment 50. The end plate 48 and the 
housing part 49 are secured together by means of through bolts 52 which 
extend through apertures formed in the stator 44 of the actuator. With the 
construction described it is therefore possible to assemble the actuator 
on the housing part 49 and then to assemble the housing part to the 
remaining portion of the housing. 
The end plate 48 also carries a fluid seal 53 which engages with the shaft 
45 to prevent any lubricant which may be contained within the compartment 
27, flowing into the compartment 28. The shaft 45 extends into the 
compartment and mounts an arm assembly 54 through which the rotary motion 
of the shaft 45 is transmitted to effect axial movement of the control 
member 17. The arm assembly 54 comprises a bush 55 which is secured to the 
shaft 45 and the bush is provided with an integral arm 56 which carries an 
upstanding pin 57. Located adjacent the seal 53 is a bush 58 which can 
move angularly relative to the shaft. The bush 58 carries a pair of arms 
59, 60 and the arm 60 is provided with an abutment 61 for engagement with 
the pin 57 and the abutment and pin are held in engagement with each other 
by means of a coiled torsion spring 62 one end of which engages the pin 57 
and the other end of which engages the arm 60 adjacent the abutment 61. 
The arm 59 carries a pin about which is mounted a roller 63, the roller 
being positioned when the two housings are secured together, to engage the 
follower 22 carried by the control member 17. The extent of movement of 
the roller 63 together with the follower 22 under the action of the spring 
21 is limited by a stop pin 64. The strength of the spring 62 is 
sufficient to transmit the torque developed by the actuator to the arm 59 
so as to move the control member 17 against the action of the spring 21 
together with any frictional resistance associated with the control member 
and the parts which move therewith. In use, an electric current is 
supplied to the stator of the actuator and the force developed by the 
actuator will be balanced against the force exerted by the spring 21 so 
that the control member 17 will assume a desired position. When the flow 
of electric current to the actuator is stopped then the spring 21 will 
return the control member to the zero fuel position. It is possible, 
however, that the actuator may seize and in such circumstances it is 
necessary to be able to cut off the supply of fuel to the engine in order 
that damage to the engine should not occur. For this purpose a manually 
operable stop control is provided and this includes a lever 65 on the 
exterior of the housing 11, the lever being carried upon a shaft 66. The 
shaft 66 within the compartment 27 mounts an arm 67 the extent of movement 
of which is determined by a pin 68 engageable against the end faces of an 
arcuate recess formed in part of the arm 67. The end of the arm 67 is 
engageable with a surface defined on the follower 22 and when the lever 65 
is moved angularly the control member will be moved to the zero fuel 
position and during such movement the spring 62 will be stressed and 
separation of the abutment 61 and the pin 57 will occur. The lever 65 is 
held in the stop position until the engine stops whereafter it can be 
released. 
The supply of electric current to the actuator is controlled by an 
electronic governor circuit to which the speed transducer 31 provides a 
signal indicative of the speed of the associated engine. A signal is also 
provided to the electronic governor circuit indicative of the setting of 
the control member 17 and this signal is obtained from a position 
transducer 69 which is housed in the compartment 50. The transducer 69 
includes a rotor 70 which is mounted upon an extended portion of the shaft 
45 and a stator 71 which is mounted within a cup shaped housing 72 having 
a peripheral flange in which is formed a plurality of apertures for the 
reception of bolts 73 engaged within the housing part 49. The stator 71 
mounts a magnetising winding and also a pair of signal windings. The 
mgnetising winding is supplied with alternating current and the signals 
obtained from the signal windings will vary in accordance with the 
relative angular positions of the rotor 70 and the stator 71. For 
adjustment purposes the stator 71 can be moved angularly about the axis of 
rotation of the shaft 45 by slackening the bolts 73. This angular 
adjustment can be carried out with the cover 51 removed and can readily be 
made when the pump is mounted on the engine or on a test bed. 
It will be seen that the two housings can be readily separated when 
servicing is required and the arm assembly 54 is housed within a 
compartment 27 which can flood with lubricant from the pump. The 
compartment 28, however, is isolated from the compartment 27 by a simple 
form of seal which is of well known construction and furthermore, provides 
minimum frictional loss.