Note: Descriptions are shown in the official language in which they were submitted.
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Description
Engine Governor With Dual Regulation
Technical Field
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This invention relates to a governor for fuel
injec-ted internal combustion engines, and more specifi-
cally, to such a governor that provides multiple;amounts
of regulation.
Background Art
Prior art of possible relevance includes the
following United States patents: 2,563,822 issued
August 14, 1951 to Dolza et al; 2,767,594 issued October
23, 1956 to Du Shane; 2,812,043 issued November 5, 1957
to Wilson; 2,821,091 issued January 28, 1958 to Benner;
2,825,238 issued March 4, 1958 to Lofthouse; 2,961,229
issued November 22, 1960 to Parks; 3,313,283 issued
April 11, 1967 to Miller; 3,337,870 issued April 16,
1968 to Miller; 3,532,082 issued October 6, 1970 to
Clouse; and 4,109,628 issued August 29, 1978 to Miller
et al. Of the above, perhaps the Clouse et al patent
is the most relevant.
Governors for fuel injected internal combustion
engines typically include a so-called flyweight assembly
which is driven by the engine and which, proportional
to engine speed, compresses a spring. The spring is
also compressed by a control assembly such as a throttle
linkage and the axial length of the spring, and changes
therein due to varying compression, dictates the amount
of fuel injected into the engine. In the usual case,
positioning of conventional racks which control indi-
vidual fuel injectors is proportional to the axiallength of the spring.
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The governing of the engine speea is achieved
generally as follows. For a given throttle setting,
under a no-load condition, the engine speed will be
at some predetermined value. If a load is applied to
the engine, and no commensurate increase in fuel is
provided, the engine will begin to slow down under the
load. As a result, flyweights in the governor will
move radially inwardly since the centrifugal force
moving the flyweights outwardly will decrease with the
decreasing engine speed. This movement of the fly-
weights will lessen the degree of compression of the
spring so that the spring's axial length will increase.
This change in length in turn will cause movement of
the fuel injector rack to increase the quantity of
fuel injected. With increasing fuel being injected,
engine speed will tend to increase. In a properly ad-
justed system, within a short period of time, the en-
gine will operate at a desired loaded speed generally
somewhat different than the no-load speed for the same
throttle setting.
When a loaded engine at a given throttle set-
ting and engine speed has the load removed, the engine
will begin to speed up assuming fuel supply has not
diminished. As a consequence the flyweights of the
flyweight assembly will move radially outwardly, this
time decreasing the axial length of the spring. This
in turn will cause movement of the fuel injector rack
to decrease the amount of fuel being injected thereby
decreasing engine speed. Again, in a short period of
time, in a properly adjusted system, the various forces
involved will balance out restoring the engine to a
desired no-load engine speed, generally somewhat dif-
ferent than the loaded speed for the same throttle set-
ting.
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In the usual case, the no-load speed of the
given throttle setting will be somewhat higher than
the loaded speed for the same -throttle setting, although
such is not always the case. The differences between
the two speeds, that is, no-load speed and loaded speed
for the same throttle setting is termed "regulation".
For example, if, at a given throttle setting, the
loaded speed of an engine is 2,000 RPM, and the no-load
speed of the engine for the same throttle setting is
2,200 RPM, there is a 10% regulation factor.
The regulation of an engine at a given throttle
setting is proportional to the spring rate of the
spring employed in the governor utilized on the engine.
However, regulation for a given engine does not remain
constant for all throttle settings. Rather, it will
vary, and may vary over a considerable range and may
even become negative, i.e., when load is removed from
the engine, engine speed would decrease. Since the
purpose of a governor is to reduce fuel flow when
engine speed increases over a desired amount, and to
increase fuel flow when engine speed decreases below
a desired amount, the negative regulation would cause
the opposite to occur and could result in an unstable
situation to the extent that a steady state engine
speed for a given loading could never be attained.
These considerations have provided considerable
difficulty in applications wherein a single fuel in-
jected internal combustion engine is intended to be
used, at different times, for two rather diverse pur-
poses. One such application is where the engine isutilized to propel a vehicle at varying speeds on one
occasion and, on other occasions, is utilized to
perform work of a completely different character typical-
ly requiring substantially constant speed engine output.
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Specific example.s would include a diesel engine utilized
in a truck as well as for power generation purposes
or for operating hydraulic systems as, for example, in
a refuse truck with refuse compaction systems.
In operating the engine to drive the vehicle,
a relatively high regulation is tolerable and even de-
sirable. For as the operator of the vehicle adds load
to the vehicle, as by driving up a hill, a relatively
high amQunt of regulation will allow the engine to
slow down noticeably indicating to the operator that a
higher throttle setting and/or change in gear ratio is
required. Conversely, in, for example, power generation
applications, a low am~unt of regulation is desirable to
prevent severe fluctuationsin output frequency that
would be associated with fluctuating engine speeds im-
posed by varying loads.
Because of the considerations previously set
forth herein, it is not practical in the overwhelming
majority of instances to select the lowest desirable
amount of regulation required of the engine for one
purpose and apply it for the other. For example, in
one application wherein the engine is utilized alter-
natively for propelling a vehicle and for power genera-
tion, for the vehicle propulsion application, the engine
might be selected to provide 245 brake horsepower at
2100 RPM for normal highway opexation and a governor
spring selected to provide an 8.6% regulation at that
engine speed. The same governor spring, at 1300 RPM
whereat the engine would develop 150 brake horsepower
would provide a 30% regulation, totally unsatisfactory
for power generation at 1300 RPM and 150 brake horse-
power where a 3% regulation is desired.
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Conversely, if a governor spring were
selected to provide 3% regulation at 1300 RPM, it can
be shown that such a spring would provide a -7%
regulation at 2100 RP~; and of course, such negative
regulation is obviously undesirable.
Thus, in order to adapt the engine to operate
in either mode, it is necessary that some means of
changing the spring rate of the governor spring be
provided so as to provide for the two differing regu-
lations called for by the two differing applications.This, in turn, presents difficulties in terms of the
difficulty of conversion as well ~s obtaining, accurate-
ly, the desired amounts of regulation in the conversion
process. It is further compounded in applications such
as mentioned by the presence of the throttle linkage
required to provide variable engine speeds for normal
highway use. Moreover, the very nature of the con-
version in such applications requires that it occur
after the truck has been driven to a point whereat en-
gine use is to be changed and again at such point beforethe engine use is changed back to that of a truck. In
these cases, sophisticated equipment by which accurate
` change in regulation can be readily determined is sel-
dom available thus adding considerably to the lneffi-
ciency and inaccuracy of the conversion process.
Heretofore, such changes in regulation in
dual application situations has been by way of attaching
a second spring to a portion of the throttle linkage,
externally of the engine or governor. This frequently
; 30 requires the disconnection of part of the throttle
, linkage to the throttle operator for the vehicle and
requires mechanical aptitude and skill to make the
installation properly. It also requires resetting of
the engine power setting and high idle speed for the
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engine under a no-load condition which is e~tremely
difficult to do in the field where such conversions must
be made in the vast majority of cases.
Disclosure of the Invention
The present invention is directed to overcoming
one or more of the problems as set forth above.
In one aspect of the present invention, a
governor for providing at least two different amounts of
regulation for a fuel injected internal combustion engine
has a rotatable flyweight assembly adapted to be driven by
the engine. A first spring is disposed to be compressed
by the flyweight assembly proportional to engine speed.
The flyweight assembly and the first spring are adapted to
be connect~d to a fuel injection system of the engine.
A control lever is associated with the first spring in
opposition to the flyweight assembly for compressing the
first spring proportional to a desired engine speed.
There is further provided a second compressible spring
along with means for selectively engaging or disengaging
the control lever and the second spring to provide one
amount of regulation when the second spring is engaged
with the control lever and a second, different amount of
regulation when the second spring is disengaged from the
control lever.
Other objects and advantages will become apparent
from the following specification taken in connection with
the accompanying drawings.
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Brief Description of the Drawing
The single Fig. is a partial schematic,
partial mechanical drawing of a governor made according
to the invention with parts shown in section for clarity.
Best Mode for Carrying Out the Inventlon
An exemplary embodimen~ of a governor 11 made
according to the invention is illustrated in the Fig.
in connection with a diesel engine, shown schematically
at 10, and which is provided with a fuel injection
system, shown schematicalIy at 12, typically of the
type wherein the amount of fuel delivered during each
injection cycle is controlled by the position of a
reciprocal rack 14 movable in a path illustrated by an
arrow 16. The position of the rack 14, and thus the
quantity of fuel injected, is controlled by a connec-
tion, directly or indirectly, to the toes 18 of a plu-
rality of flyweights 20, only one of which is shown.
The flyweights 20 are mounted by pivots 22 and
additionally, are rotatable and adapted to be driven by
the engine 10 as schematically illustrated at 24. Various
constructions ~or the flyweights 20, the pivots ~2 and the
rotatable drive 24 are ~ell known and form no part of the
present invention.
The toes 18 of the flyweights 20 bear against
a plate 26 abutting one end of a main governor spring
28. The opposite end of the spring 28 is abutted by a
plate 30 which in turn is positioned by one end 32 of
a control lever 34 and again, the construction can be
according to any known means. The control lever 34
is operable, as will be seen, to compress the spring
28 in accordance with a desired throttle setting. ~t
the same time, the toes 18 of the fl~eights 20 operate
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to compress the spring 28 dependent upon actual engine
speed. The position of the rack 14, and thus the quan-
tity of fuel injected, is dependent upon the position
of the lefthand end of the spring 28 as viewed in the
Fig. which in turn is dependent upon the amount of
compression of the spring 28 as well as the relative
positions of the control lever 34 and the flyweights
20. For the configuration illustrated in E'ig. l,
as engine speed decreases, the amount of centrifugal
force on the flyweight 20 will decrease and the com-
pression of the spring 28 will decrease while at the
same time moving the flyweight 20 in a counterclockwise
direction about the pivot 22 thereby moving the rack
14 to the left to increase the amount of fuel injected.
Conversely, as engine speed increases, the centrifugal
force applied to the flyweight 20 will increase thereby
causing the same to pivot in a clockwise direction about
the pivot 22 to increase compression on the spring 28
thereby moving the rack 14 to the right to decrease the
quantity of fuel injection. Analysis will show that
mo*ing the end 32 of the control lever 32 to the right
will have the effect of causing the rack 14 to move to
the right to decrease fuel quantity while moving the
end 32 to the left will ultimately result in an increas-
ing fuel flow.
Movement of the lever 34 is effected, in onemode of operation, by a throttle linkage shown sche-
matically at 36. The throttle linkage 36 is connected
to a rotary shaft 38. The lever 34, intermediate its
ends, includes at least one apertured tongue 40. The
aperture 42 in the tongue mounts the lever 34 for ro-
tation on the shaft 38. That is, the lever 34 is notfixed to the shaft 38 for rotation therewith but may
rotate relative thereto for certain conditions tobe seen.
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The shaft 38 fixedly mounts a collar 44 which
in turn includes an axial projection 46 which is de-
signed to overlie one of the tongues 40. One side sur-
face 48 of the projection is adapted to engage an edge
50 of the tongue 40 when the shaft 38 is rotated suf-
ficiently clockwise to cause engagement between the two.
When the side surface 48 and the edge 50 are not in
engagement with each other, relative rotation between
the lever 34 and the shaft 38 may occur.
The end 52 of the lever 34 opposite the end
32 is bifurcated as by a central slot having a bottom
shown at 54. Received within the slot is an elongated
piston rod 56 mounting a piston 58 on one end thereof.
The piston 58 is received reciprocally in a cylinder
bore 60. Fluid under pressure may be ported by means
61 to the left side of *he piston 58 to dxive
the same to the solid line position illustrated in the
Fig. within the bore 60. The bore 60 also contains a
return spring 62 ~or driving the piston 58 to the dotted
line position within the bore 60.
The end of the piston rod 56 remote from the
piston 58 mounts a retainer 64 against which is abutted
a stepped bushing 66. Reciprocally mounted on the piston
rod 56 is an oppositely directed, but similar stepped
bushing 68 and a compressible coil spring 70 is mounted
between flanges of the respective bushings 66 and 68.
The bifurcated end 52 of the control lever 34 is abutted
by the bushing 68 when the piston 58 is in the solid
line position illustrated in the drawing. Conversely,
when the piston 58 is shifted to the dotted line posi-
tion illustrated in the Fig., the bushings 66 and 68 and
the spring 70 are moved to the do~ted line position il-
lustratPd along the reciprocal path of the piston rod 56
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to a location completely disengaged from the end 52 of
the lever 34. Such a position is sufficiently remote
that no contact with the lever 34 will be established
even when the lever 34 is in its most counterclockwise
position shown at 34' in the drawing.
When the piston 58 is moved to the solid line
position, at some point in such movement, engagement
will be established between the lever 34 and the bushing
68 with the result that the spring 70 will be compressed
to scme predetermined degree and thus tend to bias the
lever 34 against the main governor spring 28.
The degree of compression of the spring 70 will
depend upon the extent to which the piston 58 moves to
the right as viewed in the Fig. and this is limited by
an adjustable stop 72 in the form of a threaded shaft
having a end 74 which may abut the piston 58. The
adjustable stop72 is threaded in an end cap 76 for the
bore 60 and extends externally thereof to terminate in
a slotted operator 78. A screwdriver may be inserted
in the slotted operator 78 to adjust the axial position
of the stop 72 within the bore 60 and once the desired
position is attained, a lock nut 80 may be tightened
to maintain such positioning.
The end cap 76 closes one end of the bore 60 in
a housing part 82 which in turn is fastened to a main
housing 84 by means of cap screws 86 or the like. The
housing 84 extends about the various components illustra-
ted, the major ones of which include the flyweight as-
sembly, the springs 28 and 70, the control lever 34, the
control shaft 38, the limited lost motion connection
defined by the side surface 48 and the edge 50, and with
the housing part 82 enclose the piston 58 as well as the
adjustable stop 72.
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Industrial Applicability
While the invention has utility in any engine
application wherein dual regulation of the engine 10 is
desirable or required, for purposes of illustrating its
industrial applicability, it will be considered in con-
nection with the example previously offered, that is,
an engine 10 intended to develop 245 brake horsepower at
2100 RPM with 8.6% regulation for propelling a truck
in normal highway operation and for developing 150 brake
horsepower at 1300 RPM with a 3% regulation. '
After selection of an appropriate engine 10 and
fuel injection system 12 is made,and''a parti'c'ular-gove-rnorll
operable therewith has been selected, the main governor
spring 28 is chosen by known methods to have a spring
rate that will provide the 8.6% regulation desired at
2100 RPM. The throttle linkage 36 is placed in the low
idle position, for example, one whereat engine speed
will be approximately 600 RPM under a no-load condition.
The collar 44 is then fixed to the shaft 38 at an angular
position whereat the side surface 48 of the projection
46 is in virtual contact with the edge 50 when the lever
34 is positioned with respect to the fl~weights 20 to
provide for a positioning of the rack 14 corresponding
to 600 RPM under no load.
The throttle linkage 36 is such as to ro~ate
the shaft 38 in a clockwise direction as viewed in the
Fig. when an increasing throttle setting is desired and
when such occurs, the projection 46 engages the lever
34 to rotate the same clockwise and compress the main
governor spring 28 as required by the operator of the
vehicle in normal highway use.
At this time, the piston 58 is in its dotted
line position, being urged thereto by the return spring
62 and does not affect engine operation.
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When it is desired to change the regulation
on the engine 10 for power generation, the throttle link-
age 36 is returned to its low idle position, typically by
a spring in the linkage itself without any intervention
by the operator. Fluid under pressure is applied by means
61 to the left side of the piston 58 to drive the same
against the stop 72. This in turn brings the bushing 68
into contact with the lever end 52 and provides some degree
of compression of both the spring 70 and the spring 28.
It will be appreciated that upon such occurrence, the
springs 28 and 70 will be acting in series against the
toes 18 of the flyweights 20 and thus, the spring rate
of the system will be different from the spring rate of
the spring 28 alone. The spring 70 is chosen to have a
spring rate which, when the geometry of the lever 34 is
also considered, when combined with the spring rate of
the spring 28 will provide a system spring rate that
will correspond to a 3~ regulation at 1300 RPM. The
stop 72 is, of course, adjusted to limit movement of the
spring 70 to a position that provides the desired fixed
engine speed, here 1300 RPM.
When it is desired to revert to the higher
engine speed and higher percent regulation, fluid pressure
applied to the piston 58 is released by means 61 and the
return spring 62 will move the spring 70 out of contact
with the control lever 34 and engine regulation will be
solely under the influence of the main governor spring 28.
Those skilled in the art will appreciate that
manyadvantages accrue from the invention. Firstly, and
most importantly, accurate dual regulation is provided.
Secondly, the operator, in changing from one regulation
to another, need do no-thing more than "push a button" to
cause the piston 58 to be pressurized or vice versa.
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Alternately, a solenoid could be used in lieu of the
piston 58. No mechanical skill or understanding of the
system is required and the operator need not make any
mechanical alteration to the system which could then
be time consuming, possibly improperly accomplished,
and inaccurate.
The two regulations may be accurately set at
the factory using sophisticated equipment such as
dynomometers and ordinarily will require no adjustment
lO in the field. However, where adjustment may be required, -,
it'can be accomplished through the simple act of uti-
lizing the external operator 78 for the stop 72.
All regulating components are contained within,
the housing defined by elements 82 and 84 and therefore
are essentially tamperproof.
There is no need to disconnect any part of the
throttle linkage 36 when conversion from one regulation
to another is made by reason of the limited lost motion
connection between the throttle linkage and the control
lever 34 provided by the projection 46 and its side
surface 48 and the edge 50.
The system is practical in applications where
more than two amounts of regulation are required simply
by lengthening the lever end 52 and adding additional
components corresponding to the sprlng 70 and the piston
58 configured to provide additional system spring rate
variations.
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