Note: Descriptions are shown in the official language in which they were submitted.
196i
Background of the Invention
.__
The background of englne yovernors in general, and a
full disclosure of my previous invention in combined engine and load
speed governors, is contained in my U.S. Patent No. 4,1~1,103 issued
on January 1~ 19~0. ~ly aforesaid engine governor was of a dyna-
mically-surging type which allowed engine speed to oscillate
rather rapidly (and forcefully for a vehicle in a lower gear
ratio) about its predetermined limit.
While such oscillations are not damaging to the engine
and may be helpful in encouraging a truck driver to "get out" of
a lower gear ratio and into a higher ratio where the engine will
be operating more efficiently, it is also advantageous to have an
engine governor which allows the engine to be accelerated to its
predetermined speed limit with less overshoot beyond that limit
than provided by my previous dynamically-surging governor, and
which will thereafter bring the engine quickly to run in clcse
approximation to the predetermined speed limit, wandering from it
only perhaps 1~ when in a very low gear and less in higher gears,
and that probably not on any cyclical basis. Such action is
obtained basically by positioning the engine throttle to a pre-
determined reference position upon acceleration of the engine to
a predetermined speed and actuation of the engine governor there-
by, rather than by driving the throttle toward a full-closed
position as ir. my previous patent application aforesaid.
Such a smooth and gentle control is advantageous for
full economy, and for driver and/or passenger comfort, especially
for an application such as a school bus engine, and is typical of
my present invention which provides such an engine speed
governor and also combines it with a load speed governor essen-
tially like that of my aforesaid patent. ~he
~.ti~.~6~
present combination functions to safely control engine and load
speeds generally like the combination of my aforesaid patent
application, except smoothly, without the previously-experienced
dynamic-surging in engine speed control mode. The present in-
vention includes an overspeed control which acts to close the
throttle beyond the reference position toward a completely
closed position in the event of prolonged speeding outside a
normal range above the predetermined speed limit (as would be
possible for a driver proceeding downhill with the accelerator
pedal "floored" or calling for maximum throttle opening), thereby
retaining generally the feature of my previous invention which
acted to close the throttle toward a completely closed position
whenever the engine speed remained anywhere above the predeter-
mined limit.
Like my previous invention, the apparatus of the pre-
sent invention is a standard unit which may be connected to the
standard carburetor, ignition system, and speedometer cable of
any engine and vehicle, so that it may be applied at the factory
or in the field without inconvenience, and spare parts for this
apparatus will be the same for any engine-vehicle combination.
However, my present invention also contemplates the use of a
lost-motion type overriding carburetor linkage (in place of
the equally useable linkage-lengthening capsule disclosed in
my aforesaid patent application) which gives a more conventional
feel to the accelerator pedal, but with a more complicated
parts situation, since each different engine-carburetor com-
bination may require different linkage parts and adaptations.
Also, use of a conventional pulse generator connected to the
tachometer drive of a Diesel engine is contemplated for appli-
cation of the apparatus of the present invention thereto.
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Summary of the Invention
In an engine governor for limiting the speed of an
engine to a set speed and having movable overriding means for
limiting the flow of energy-supplying means to the engine, the
improvement including means for selectively moving the overriding
means for suitably limiting the flow at rates of moving whereby
the speed of the engine in unloaded condition follows the moving
of the overriding means with only insignificant overrunning of
the set speed upon cessation of the moving of the overriding
means. The governor may have means for moving the overriding
means in flow limiting direction to a predeterminted reference
position upon actuation of the governor. The governor of the
present invention may also have means for moving the overriding
means from the reference position to suitable other positions for
limiting the flow to that for operating the engine at speeds in
close proximity to the set speed.
The present governor may have means for actuating the
governor when the engine is accelerated to a predetermined speed,
such as the set speed, and the means for moving the overriding
means to suitable other positions may include means for moving
the overriding means in a direction away from the reference
position and opposite to its limiting direction upon its arrival
thereat. Means for causing continuing moving of the overriding
means in the aforesaid opposite direction when the engine is
operating at speeds below the set speed may be included also.
Preferably, the present governor may be actuated at a
predetermined speed which is slower than -the set speed, and may
have means for causing the overriding means to move back in
limiting direction to the reference position, after its moving
away from the reference position in opposite direction to the
361
limiting direction, when the engine is operating at speeds at and
above the set speed. The governor may also have means for respec-
tively continuing the aforesaid moving away from and to the refer-
ence position while the engine is operating at speeds at, and ~ith-
in a predetermined range above, the set speed. The means for
moving the overriding means to other positions may include means
for causing the moving thereto to occur at a substantially slower
rate than the moving of the overriding means in the flow limiting
direction upon actuation of the governor, and such slower moving
may be only in the direction opposite to the limiting direction.
In the preferred embodiment, the present governor has
means for monitoring the speed of the engine for detecting an
acceleration thereof to a predetermined speed which is slower than
the set speed from another lower predetermined speed within a
predetermined time period, and for actuating the governor upon
detection of such an acceleration. Means is also provided in a
preferred embodiment having the repetitive moving away from and
to the reference position for causing the overriding means to
cease said repetitive moving when the engine is accelerated to
operate at a speed exceeding the aforesaid predetermined range,
and to move past the reference position in limiting direction for
decelerating the engine to operate at a speed within the pre-
determined range. Means is also provided to cause the cessation
of said repetitive moving and to cause the overriding means to
move away from the reference position in a direction opposite to
the limiting direction upon subsequent operation of the engine at
a speed below the set speed. The preferred embodiment is an engine
speed governor and load speed governor combination for an engine
and load connected by a multi-ratio transmission and having a
driver-operated means for controlling the flow of energy-supplying
means to the engine, overriding means for limiting that flow, means
for selectively operating the overriding means in flow limiting
direction and opposite thereto, high engine speed responsive means
for independently causing the operating means to operate in the
limiting direction, high load speed responsive means for indepen-
dently causing the operating means to operate in the limiting
direction, and low engine speed responsive means and low load
speed responsive means for jointly causing the operating means
to operate the overriding means in the direction opposite to the
limiting direction when concurrently responsive, this combination
being characterized further by the foregoing improvements as
described in this summary taken alternatively or in combination
as desired.
Brief Description of the Drawings
Fig. 1 is a diagrammatic view showing the engine and
load speed governor of the present invention connected to a trans-
missionl carburetor linkage, and accelerator pedal of an engine
connected to vehicle wheels by the transmission;
Fig. 2 is a diagrammatic view showing mechanical details
of the governor proper;
Fig. 3 shows the throttle lin~cage of Fig. 1 in a differ-
ent configuration;
Fig. 4 shows the switch plate of the present governor as
connected to the electronic control portion thereof;
Fig. 5 shows a schematic circuit diagram of an electro-
nic control providing for positioning the throttle-limiting at a
reference position;
Fig. 6 shows a schematic circuit diagram of the portion
of an alternate electronic circuit providing slow motion of the
throttle-limiting means in one direction; and
361
Fig. 7 shows a schematic diagram of a portion o an
electronic circuit providing slow motion of the throttle-limiting
means as desired.
tion o~ the Preferred Embodiment
In the illustrated preferred embodiment, as shown
schematically in Fig. 1, an internal combustion engine 20 has
connec~ed thereto a transmission 22 for drLving a load 24 such as
the drive wheels of a truck. The transmission 22 is of the usual
construction which allows automatic or manual shifting of the gears
therein to provide various ratios of speeds between the engine 20
and the load 24. Typically, in a truck, the transmission 22 is
shifted into "low gear" to start the load 24 moving at very low
speeds, as from a standing start, so that the engine 20 can operate
at a rotational speed of thousands of revolutions per minute,
where it operates most efficiently, while the load 24 is eased
into motion by a friction clutch or hydraulic connection (not
shown) included in the transmission 22, and a very large torque is
applied through the gearing of the transmission 22 ~-o the axle 26
of the drive wheels 28 of the load 24, it being understood that
the engine 20 and the transmission 22 are attached to and part of
the load 24. As the drive wheels 28 pick up speed, and before the
engine 20 reaches some safe limit to its short term rotational
speed, such as 4,400 rpm for example, it is desirable to shift
the transmission 22 into a "higher gear" ratio where the wheels 28
will turn at a higher rpm relative to the engine 20, and the power
of the engine 20 will be applied through the transmission 22 to
the wheels 28 to farther accelerate their speed until the engine 20
again approaches its safe rotational speed. This process of
accelerating the engine 20 toward its maximum speed and shifting
into a "higher gear" continues until the wheels 28 are driving the
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61
load or truck 24 along at a safe and suitable road speed, at which
time the transmission will be in its nominal "high gear", the load
or truck 24 may be running along at 50 miles per hour, and the
engine 20 may be revolving at 3,000 rpm.
It is desirable that the road speed of the load 24 should
be controlled or governed to some safe speed such as 55 miles per
hour and it is also desirable that the speed of the engine 20 be
governed or controlled to its maximum safe speed for long term
operation, such as a speed of 4000 rpm, and the engine and load
speed governor 30 of the illustrated embodiment of this invention
has overriding means for limiting the flow of the energy-supplying
means or fuel to the engine to automatically and selectively con-
trol both speeds with peculiar advantages to each.
The governor 30 is shown schematically in Fig. 1 connec-
ted to the load side of the transmission 22 by the flexible rotary
cable 31, which may be the typical "speedometer cable", and which
transmits rotary motion at a speed proportional to the speed of the
wheels 28. A gear 32 connected to the cable 31 inside the housing
33 drives an output gear 34 which is connected to a speedometer
cable C for driving a speedometer S which may be located on the
dashboard of the truck cab. Governor 30 is connected to the
carburetor throttle plate 35 of the carburetor 36 of the engine 20
by a flexible pull cable 38 enclosed within a flexible sheath 40
of fixed length attached to and extended from the governor 30, as
shown in Figs. 1 and 2. The connection between throttle plate 35
and cable 38 is by means of the throttle arm 42 mounted on throttle
shaft 44 to which the throttle plate 35 is affixed, and a stud 46
fixed in the free end 48 of the throttle arm ~2 intermediately
thereof forms a mounting point for a pivotable eye fitting 50
which is permanently attached to the free end of the cable 38.
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61
The extended end of the flexible shea-th 40 is attached
to a bracket 52 mounted to the carburetor 36 for holding the end
of the sheath 40 in general alignment with the stud 46 and the
eye fitting 50 on the extending end of the cable 38. A first
tension spring 54 is stretched between a first pin 56 installed
near the extremity of the free end 48 of the throttle arm 42 and
a second pin 58 is fixed in relation to the carburetor 36 for hold-
ing the throttle plate 35 in its normally nominally closed or idle
position as shown in Fig. 1 in solid lines. An accelerator arm
60 is mounted for free rotation on the throttle shaft 44 and is
connected to the throttle arm 42 by a second extension spring 62
stretched between a third pin 64 and a fourth pin 66, the pins
being respectively fixed in the free ends of the arms 42 and 60.
The spring 62 is substantially stronger than the spring 54. A
stop 68 on an extending portion 70 of the accelerator arm 60 is
biased against the throttle arm 42 by the spring 62 under normal
idling conditions for the engine 20.
An accelerator pedal 72 is normally biased to an idle
position against a pedal stop 74 by a third extension spring 76
of suitable strength and is suitably freely pivoted on a pedal
shaft 78 for pedal actuation to a full or wide open throttle
position (indicated by the numeral 72') against a floorboard stop
80. The lower end of the pedal 72 is connected to a fifth pin
82 mounted on the free end of the accelerator arm 60 by a link 84
pivotable at the pedal 72 and the pin 82. The link 84 is of suit-
ably adjusted length to place the pedal 72, the accelerator arm 60,
and the throttle arm 42 simultaneously in their respective normal
or idle positions as shown in solid lines in Fig. 1.
When the governor 30 is in its normal or unactuated
condition, the cable 38 may be freely pulled out from its sheath
;~5~
40 by pivoting the throttle arm 42 counter-clockwise against the
bias of the spring 54. sy depressing the pedal 72 against stop
80 to its wide open position, the accelerator arm 60 will be
rotated counterclockwise -to its wide open throttle position as
shown in broken lines and indicated by the numeral 60' in Fig. l;
and the spring 62 will pull the throttle arm 42 to its wide open
throttle position as shown in broken lines and indicated by the
numeral 42'.
When the governor 30 has been actuated as described
hereinafter, and the eye fitting S0 at the extending end of the
cable 38 has been pulled back toward its normal or idle position
as shown in solid lines, the counter-clockwise movement of the
throttle arm 42 will be limited accordingly, and the spring 62
will be stretched as necessary to accommodate any mismatch between
the position of the pedal 72 and the position of the throttle arm
42~ The extreme mismatch, as shown in Fig. 3, occurs when the
pedal 72 is at the wide open throttle position and the throttle
arm 42 has been limited to its idle position by withdrawal move-
ment of the cable 38, the spring 62 is at its maximum stretched
condition, and the cable 38 extending from the governor 30 is
thereby fully overriding the call from the accelerator pedal 72
for full throttle. Intermediate positions of the pedal 72 and
the arm 60 are available at the will of the operator, as are
intermediate positions of the throttle arm 42 as permitted by the
limiting action of the cable 38.
The pedal 72 is thereby free to be positioned wherever
the operator desires, and so long as the governor cable 38 is in
its fully extended, normal, non-limiting position, the accelerator
arm 60 and the throttle arm 42 will be biased together by the
spring 62 to move as one, and the throttle plate 34 will open
61
and close according to the position of the pedal 72. If the cable
is retracted to limit the throttle opening, the spring 62 will
stretch as necessary upon depression of the pedal 72 so that the
accelerator pedal will have a generally normal feel just as a
conventional accelerator pedal and throttle linkage. The accelera-
tor pedal and throttle and carburetor linkage disclosed is
schematic and representative of infinite mechanically equivalent
variations to suit particular engine-carburetor-vehicle combina-
tions. Particularly, torsion springs may be substituted for the
tension springs disclosed, for space and configuration considera-
tions, and a similar apparatus could be adapted for use with the
control lever of a Diesel or gasoline fuel injection system, or
other means of limiting the flow of energy-supplying means to a
motor or engine, even an electric one.
The construction and operation of the load speed gover-
nor portion 86 of the present invention as shown in Fig. 2 is
generally the same as that disclosed in my aforesaid patent appli-
cation, and no further disclosure is needed herein except to point
out the additional elements incorporated therewith as shown ir
Figs. 2 and 4 to provide means for moving the carrier 88 to a pre-
determined reference position upon actuation of the engine
speed governor portion 90 of the engine and load speed governor
30:
An arcuate switch plate 92 is mounted to pivot for adjust-
ment about the carrier shaft 94 which is affixed to the housing 33
by means of a bracket 96 attached inside the housing. The plate
92 is formed of insulating material and is mounted on a metal hub
98 which is mounted for pivoting on the shaft 94. The hub 98 has
an attachment flange 100 to which the plate 92 is fastened by
rivets 102. The plate 92 is located directly behind the carrier
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61
88 within the housing 33, and the bracket 96 supports the shaft
94 between the carrier 88 and the hub 98. The shaft 94 and hub
98 mounted thereon extend rearwardly through an opening in the
housing 33. Outside the housing 33 a crank arm 104 is attached
to the hub 98 and has an extending end in which is mounted a
pivotable stud 106 having a threaded cross hole into which is
threaded an adjustment screw 108. The shank of the screw 108 at
the head end thereof passes through a clearance hole in a stud 110
fastened to the outside of the housing 33, and a compression
spring 112 mounted on the screw 108 between the studs 106 and 110
holds the two studs 106 and 110 biased firmly apart to a distance
limited by the head 114 of the screw 108.
Thus, rotary adjustment of the screw 108 acts to change
the distance between the studs 106 and 110, thereby pivoting the
switch plate 92 about the shaft 94 to set the plate 92 at any
desired position within a suitable range of adjustment. Such
positioning is desirable in order to angularly place a reference
position contact 116 as desired in relation to the carrier 88.
The contact 116 is mounted on the switch plate 92 in arcuate rela-
tion to the hub 98, and is connected to an electrical lead 118
for connection to the electronic control portion 119 of the
governor 30 as explained hereinafter. The contact 116 extends
clockwise from a generally central portion of the arcuate shape
of the plate 92, and a somewhat similar limiting contact 120 is
mounted on the plate 92 spaced a small gap 122 counter-clockwise
from the contact 116 and extending along the same arc as contact
116 in a counter-clockwise direction generally to the left side
of the plate 92. The contact 120 is connected to an electrical
lead 124 for connection to the electronic control portion 119.
An electrically conductive spring leaf 126 having a
carrier electrical contact 128 at one end thereof is fastened at
the other end to the rear side of the carrier 88 by rivets 130
and is sprung away from the carrier 88 for spring-biased contact
with the switch plate 92 and the contacts 116 and 120 along the
arcs thereof wherever the carrier 88 may be positioned as explained
in my aforementioned patent application or to be explained herein-
after. By its connection to the carrier 88, the contact 128 is a
grounding contact so far as the electronic control portion of the
governor is concerned. In Fig. 4 the carrier 88 has been broken
away, and the spring leaf 126 and the contact 128 are shown in more
detail in relation to the switch plate 92. The left, or counter-
clockwise end of the reference position contact 116 forms the
actual reference point or position to which the carrier contact
128 is moved and homed for establishing a reference position for
the carrier 88 and thereby the overriding means for limiting the
flow of energy-supplying means which is an object of the present
nvention .
A reversible electric motor 132 is included in the
electronic control 119, as are the accelerate or open throttle
contact 134, the decelerate or close throttle contact 136, and
the grounding contacts 138 which control the motor 132 at the
command of the load speed governor 86 to turn the lead screw 140
which in turn causes the carrier 88 to move in rotation on the
shaft 94.
In simplest terms, the governor 30 of the present inven-
tion functions as follows: In the absence of a signal to the
contrary, either from the load speed governor 86 or the engine
speed governor 90, the load speed governor 86 acts to move the
carrier 88 to its extreme counter-clockwise, rest, or wide-open-
throttle position as shown in Fig. 2, where the flow of fuel or
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energy~supplying means to the engine 20 is not limited at all by
the governor 30, but is dependent upon the operator-positioned
accelerator and throttle linkages as described hereinbefore and
in my aforementioned prior patent application. Then, in the
absence of a load speed sufficient to actuate the load speed gover-
~ ~.
,, r~ nor 86 as described in my aEoresaid patent _~p~Le~on (e.g. whenthe transmission 22 is in neutral, or in a lower gear ratio whexe
the engine must reach a speed far above the governed speed in
order to actuate the load speed governor 86) the electronic con-
trol 119 may assume control of the governor 30 as explained here-
after.
The electronic control 119 monitors the speed of the
engine 20 for detection of operation of the engine at a pre-
determined governed or set speed such as 4000 rpm, and at at least
three other speeds having predetermined relations to the set
speed: A precall speed which may be 600 rpm below the set speed,
a close throttle speed which may be 400 rpm below the set speed,
and an overspeed speed which may be 300 rpm above the set speed.
Upon acceleration of the engine and detection of the
precall speed, 3400 rpm in this example, the control 119 initiates
a timing circuit, and, if within a predetermined time period such
as .2 seconds, the close throttle speed of 3600 rpm is detected,
then the control 119 will connect electrical power (from the
engine electrical system) to the motor 132 to cause it to rotate
in close throttle direction, thereby turning the lead screw 140
appropriately to cause the carrier 88 to move in clockwise or close
throttle direction away from its rest position. Once initiated,
this close throttle movement of the carrier 88 will continue
until the carrier contact 128 touches the reference position con-
tact 116, thereby automatically moving the carrier 88 to a reference
~ ~196~
position which has been preset to allow an unloaded enyine speed
just slightly above the set speed (4000 rpm in this example) of
the electronic control 119. If acceleration of the speed of the
engine 20 from 3400 rpm to 3600 rpm takes longer than .2 seconds,
the control 119 takes no further action, and the engine speed
governor 90 remains unactuated until the engine speed reaches
the 4000 rpm set speed, at which time the control 119 energizes
the motor 132 in the close throttle direction to move the carrier
88 to its reference position.
If upon arrival of the carrier 88 at its reference
position, the engine speed is detected by the electronic control
119 to be at 4000 rpm or within a range thereabove extending to
4300 rpm (the overspeed speed in this example), then the electronic
control 119 will react to the carrier contact 128 touching (there-
by making electrical contact with) the reference position contact
116 by reversing the energization of the motor 132 to the open
throttle mode, whereupon the carrier 88 is moved counter-clockwise
until the carrier contact 128 breaks contact with the reference
position contact 116. Once the electrical circuit between con-
tacts 128 and 116 is broken, a continuing detection of an engine
speed within the aforesaid range of 4000-4300 rpm causes the con-
trol 119 to again energize the motor 132 in the closed throttle
direction to drive the carrier contact 128 back to the reference
position contact 116 for continuing repetition of the open
throttle-close throttle driving cycle in a so-called "alternating
circuit" mode of operation so long as the engine speed remains
in the 4000-4300 rpm range. In the preferred embodiment of the
present invention, the movement of the carrier contact during the
repetitive cycle may be only .005-.010 inch, so that the cable 38
may move little or none, what with normal clearances and backlash
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~51S~
in the apparatus. The throttle plate 35 is thus limited to being
opened to a corresponding reference position, even though the
accelerator pedal may be fully depressed, and will initially be
closed to the reference position by the overriding action of the
carrier 38. If upon arrival o~ the carrier contact 128 at the
reference contact 116, the engine speed is below 4000 rpm, the
control 119 will reverse the motor 132 to the open throttle
direction and release control of the motor 132 to the load speed
governor contacts 134 and 138 for return of the carrier 88 to its
wide-open-throttle or rest position.
If upon arrival of the carrier contact 128 at the
reference contact 116 the engine speed has reached the overspeed
speed of 4300 rpm, then the control 119 will cause the electrical
contact between contacts 128 and 116 to be ignored, and the carrier
88 will continue to be driven in close throttle direction past the
reference contact 116 until the control 119 detects engine speed
within the 4000-4300 rpm range or the carrier reaches its maximum
close throttle, idle, or overspeed position. This condition
normally will occur only when an overrunning load has been applied
to the governed engine, such as running the associated vehicle down
a steep hill, or when the switch plate 92 has been miss-set. Upon
deceleration of the engine speed to within the 4000-4300 rpm range,
the control 119 will energize the motor 132 in the open throttle
direction until the carrier contact 128 loses contact with the
reference position contact 116 and the governor 90 will revert to
the alternating circuit mode of operation.
In normal operation, three operating conditions should
be considered, the first being that where the engine cannot main-
tain the governed or set speed with the throttle plate 35 at its
reference position because of a heavy load such as an uphill grade,
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51~1
so that engine speed falls below the exemplary 4000 rpm set speed
after having attained it under Eull throttle and actuated the
carrier 88 toward its reference position to 1imit the throttle
plate 35 to some lesser opening. As soon as the engine reacts to
moving the throttle plate toward its reference position by decele-
rating below 4000 rpm, the governor 90 will be deactuated by the
control 119, and the carrier 88 will be moved toward open throttle
until the engine again accelerates to the set speed of 4000 rpm,
which will reverse the carrier into movement toward closed throttle
once again--thus the throttle plate 35 will oscillate through a
iimited range of positions as necessary to hold the engine speed
very near the set speed, the frequency and magnitude of the
oscillations of the throttle plate 35 and the engine speed being
determined by the interrelationships of engine power, load applied,
and gear ratio being used in the transmission 22, or accelerational
decelerational capacity of the engine, together with the response
speed of the motor 132 and its screw 140 driving the carrier 88.
The second operating condition is that where the reference
position of the throttle plate 35 is just sufficient to maintain
the engine speed in the 4000-4300 rpm range--in this case, the con-
trol 119 will keep the governor 90 in its alternating circuit mode
of operation, and the engine speed may wander within the 4000-4300
rpm range while the throttle plate 35 is held at its reference posi-
tion (assuming that the accelerator pedal 72 is held depressed at
least sufficiently to open the throttle plate 35 that far). If the
engine speed goes outside the 4000-4300 rpm range, the governor 30
will be de-actuated below 4000 rpm or go into the overspeed mode of
close throttle drive as explained hereinbefore above 4300 rpm.
The third operating condition is that where an over-
running load such as a moderate downhill grade is imposed on the
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61
engine 20 such that when -the goyernor 30 has acted to close the
throttle plate 35 to its idle or overspeed position, as previously
explained, then the engine speed drops below 4300 rpm, thereby
causing the carrier 88 to move back toward its reference position.
Assuming the accelerator pedal 72 being sufficiently depressed, the
throttle plate 35 will open until the engine speed again goes above
4300 rpm and the control 119 causes the carrier to move in close
throttle direction again, and the cycle will repeat, allowing small
oscillations of the throttle plate 35 about an average position
permitting an engine speed of about 4300 rpm and small oscillations
of the engine speed about 4300 rpm. Here again, the parameters of
engine accelerational/decelerational ability, gear ratio, and
carrier 88 response time determining the period and magnitude of
the oscillations.
Operation of the engine 20 at speeds below the set
speeds is perfectly free of any control by the engine speed governor
90 except in the aforementioned case of rapid acceleration between
precall and close throttle speeds of 3400 and 3600 rpm respec-
tively.
An electronic logic module 144 (not shown in Figs. 1 and
2) for the electronic control portion 119 of the governor 90 is
mounted within the housing 33 of the governor 30. As shown
schematically in Fig. 5, the module 144 includes conventional
integrated circuits and electronic components which operate as
described below to receive negative pulse signals from an internal
combustion engine ignition coil (or alternatively from a pulse
generator connected to a Diesel engine or other prime mover~, and
signals from the switch plate contact 116 and the open and close
throttle contacts 134 and 136 respectively, in order to control
the reversible electric motor 132 as described hereinbefore.
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36i
To control engine speed a me-thod is first needed to detect
the engine speed. This is accomplished by a requency to voltage
converter. The engine speed is proportional to the number of
ignition pulses per minute as monitored at the negative terminal
of the ignition coil of the engine 20. These pulses are fed into
terminal A. Voltage divider resistors Rl and R2 are selected so
that the transistor Ql (normally off) will turn on once for each
ignition pulse. A resistor R3, a variable potentiometer Pl and
a capacitor Cl form a resistor-capacitor timing network. For each
ignition pulse, the transistor Ql will turn on, and in turn fully
discharge the capacitor Cl. As the engine speed increases, the
transistor Ql will turn on more frequently. With the transistor
Ql off, the capacitor Cl starts to charge. As the volta~e rises
on the capacitor Cl to approximately 1/2 of the ten volt supply
voltage, the logic norgate ICl-l of the quad norgate ICl will have
its output (pin 3) change state from high to low. When the output
is high, the capacitor C2 is being charged through the resistor R4.
A change in output from high to low will cause the capacitor C2 to
be discharged. By properly selecting the values of R3, Pl, Cl, R4
and C2, an average voltage will appear on the capacitor C2 which is
proportional to engine speed. The faster the engine speed (ignition
pulses) the higher the voltage, the slower the engine speed the
lower the average voltage.
A voltage comparator circuit is used to determine when
various predetermined engine speeds occur. The speeds are:
precall, close throttle, governed, and overspeed. The circuit
consists of a quad voltage comparator IC2 and five resistors Rl9,
R5, R9, R10, and Rll which set the individual voltages at which
each comparator functions.
~he precall and close throttle comparators operate
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61
cooperatively in sequence. Their purpose is to determine whether
the engine is accelerating in speed so fast that the engine speed
governor should be actuated before the set speed is reached. If
this condition occurs, the precall and close throttle comparators
IC2-1 and IC2-2 act together to start the governor operating even
before the predetermined governed speed is reached. A typical
example would have the precall speed set at 3400 RPM, the close
throttle speed at 3600 RPM, the governed speed at 4000 RPM and
the overspeed at 4300 RPM. If the engine should accelerate between
3400 and 3600 RPM within 200 milisec, this rate of acceleration
would cause the close throttle norgate ICl-2 to function to operate
and activate the governor. When the engine speed increases at a
slower rate the precall close throttle circuitry is inoperative
and plays no part in the operation.
Upon reaching 4000 RPM, the governor or set speed
comparator IC2-3 begins its normal governing. At 4300 RPM the
overspeed comparator IC2-4 turns on, causing the governor 90 to
go toward completely closing the throttle plate 35.
When the engine acceleration exceeds the normal governor
reaction capability, the close throttle comparator IC2-2 causes
the control 119 to start the governing process prior to 4000 RPM
being reached. In the event of such a condition, the precall
and close throttle comparators IC2-1 and IC2-2 provide signals
to the close throttle norgate ICl-2 which in turn provides a
signal to a flip-flop circuit composed of the two norgates IC1-3
and IC1-4. With the proper signal the flip-flop circuit is set
so that the output of pin 4 of ICl-4 goes high and acts through
the norgates IC3-1 and IC3-2 of the quad norgate IC3 to cause the
transistor Q2 to drive the motor 132 and the associated carrier
contact 128 in the close throttle direction. Upon the carrier
--19--
contact 128 reachin~ the normally open re~erence position contact
116 of the switch plate 92 the flip flop circuit receives a
reset signal from the norgate IC3-3 at pin 5 of the norgate ICl-4
and pin 4 thereof goes low. The precall close throttle function
cannot reoccur unless the engine speed drops below the 3400 RPM
precall level, and only then could the process be repeated.
The quad norgate IC3 comprises the logic circuitry which
allows the electronic logic module 114 to control the governor 90
in proper sequence. Pin 6 of norgate IC3-1 is normally low. With
a high signal at pin 6, the output pin 4 of norgate IC3-1 goes
low and causes the output pin 10 of norgate IC3-2 to go high. This
will turn on the transistor Q2 and drive the motor 132 in the
close throttle direction. The motor continues driving the carrier
88 in the close throttle direction until its contact 128 reaches
the reference position contact 116. Grounding the reference con-
tact 116 causes pin 2 of the norgate to go low and pin 3 thereof
to go high. Pin 3 going high will cause pin 10 of the norgate IC3-2
to now go low. When pin 10 goes low, it causes pin 11 of the
norgate IC3-4 to go high which turns on the transistor Q3, driving
the motor 132 in the open throttle direction. The carrier 88
going in the open throttle direction will remove the carrier
contact 128 from the reference contact 116 and change pin 2 of the
norgate IC3-3 from low back to high and the process will keep
repeating. This operation is known as the alternating circuit
feature since the motor 132 will alternately drive the carrier
contact 128 on and off the reference contact 116. The amount of
movement is very small and effectively keeps the carrier 88 at its
reference position at the threshold of the reference position
contact 116.
Should the engine speed keep increasing to 4300 RPM as
-20-
61
does happen in some isolated ins-tances, it is necessary that the
alternating circuit mode be overridden so that the motor will
drive the carrier con-tact 128 past the threshold of the reference
contact 116 fully in the close throttle direction. When such an
instance is detected by the overspeed comparator IC2-~, pin 14
thereof goes high and continually holds pin 3 of the norgate IC3-3
low. This overcomes the effect of the reference contact 116 being
grounded at pin 2 of the norgate IC3-3 and allows pin 10 of the
norgate IC3-2 to remain high as long as the overspeed condition
exists. Dropping below the overspeed value of 4300 RPM allows
the governor comparator IC2-3 circuitry to govern as normal.
The Zener diode ~1 in series with the resistor R 18
across the 12 volt battery supply voltage, as shown in Fig. 5,
provides a stabilized 10 volt supply for the logic module 144 as
indicated at various points therein.
An alternative second embodiment of the engine speed
governor 90 provides for operation of the motor 132 (and thereby
the carrier 88) at a substantially slower speed in open throttle
direction than in close throttle direction--approximately 15-18
seconds to rotate the carrier 88 from idle position to wide-
open-throttle position as compared to about 3 seconds to rotate
it from wide-open-throttle to idle position. The slower speed is
accomplished by the circuitry of Fig. 6, which shows in schematic
detail the changes and additions to the circuitry of Fig. 5--the
portions of Fig. 5 which are not repeated in Fig. 6 are identical
in both circuits. The additional resistor R20 in the connection
between the transistor Q3 and the motor 132 serves to reduce the
voltage supplied to the motor, and with the resultant reduced
speed, it is desirable that, upon arrival of 'he carrier contact
30 128 at the reference contact 116 subsequent to actuation of the
governor 90, that the contact 128 should remain at the reference
-21-
~5~
contact so long as the engine speed remains in the ~000-4300 RPM
range. Therefore, the pln 13 of the noryate IC3-4 is now connected
to limiting circuitry comprising the trans~stors Q4, Q5, and Q6
and their associated added components. Now, when the contact 128
touches the contact 116, the motor 132 is turned off, and so long
as the engine speed remains in the 4000-4300 RPM range, it remains
off. If the engine speed drops below 4000 RPM, the governor com-
parator IC2-3 will cause the motor 132 to run in open throttle
direction (at the slow speed) until the engine again rises to
4000 rpm, or until the carrier 88 moves in open throttle direc-
tion sufficiently for the carrier contact 128 to cross the narrow
gap 122 and touch the limiting contact 120 on the switch plate 92--
in either case, the open throttle drive ceases; and in the first
case the governor comparator IC2-3 causes the motor 132 to drive
in the close throttle direction, while in the second case the
carrier contact 128 remains at the limiting contact until the
engine either rises to 4000 RPM and the governor comparator IC2-3
causes close throttle drive, or the engine drops below the precall
speed of 3400 RPM and the precall comparator IC2-1 causes open
throttle drive, carrying the carrier contact 128 past its initial
contact with the limiting contact 120 toward the wide-open-
throttle position of the carrier 88.
This second, slow speed, embodiment is advantageous for
lessening engine speed oscillations, but is disadvantageous in
that the slow travel of the carrier 88 toward open throttle may
sometimes handicap the operator who is trying to get a rapid
acceleration of the engine for shifting gears.
Yet a third embodiment of my engine speed governor inven-
tion provides for normally fast travel of the carrier 88 toward its
reference position upon actuation of the engine speed governor
-22-
90 untll the carrier contact 128 moves off the limiting con-tact
120, at which the motor 132 drops to a very slow speed resulting
in clockwise movement of the carrier 88 about its shaft 94 at the
rate of about one-third RPM, which would be rouyhly equivalent to
full travel from wide-open-throttle position to idle throttle
position in about thirty seconds. An objective of this slow speed
is to move the carrier 88 in limiting control of 'che throttle
plate 35 at a slower rate than the response capability of the
engine 20, thereby minimizing engine speed oscillations. Since
the response capability of the engine will vary considerably
according to loads and gear ratios, recovery time (from the loss
of engine speed due to sudden application of a heavy load while
running at the governed speed under light load) could be somewhat
slow--however, this is not the usual condition and is overweighed
by the stability of the system for normal operation.
The relation of engine response capability rate and
throttle limiting means movement rate is a complex one, but
consider that any engine running at idle speed and having full
throttle suddenly applied will take a second or two to reach a
speed of say 4000 RPM, and if a governor acts to close the throttle
quickly to closed or idle throttle position upon attainment of
the 4000 RPM speed, the engine speed will overshoot or overrun
the 4000 RPM speed and then decelerate below the 4000 RPM speed
and undershoot or underrun it, even though the governor acts to
open to full throttle again immediately upon the speed dropping
below 4000 RPM. This may cause oscillations of engine speed of
1000 RPM or more in an unloaded engine, rapidly enough to be
disturbing to its operator, and resulting in a governor with very
poor regulation. This is an example of a throttle limiting means
moving at a very much faster rate than the engine response capa-
bility rate, and results in out-of-phase operation of engine and
-23
6~
throttle as explained in my aforesaid ~ patent a~ ~a~n.
~ .
On the other hand, it has beell found tha-t where the
throttle can only be moved between idle and full positions over
a period of about twenty seconds or more, then in-phase operation
of engine and throttle occurs, as in the present invention, and
very good governor regulation can be obtained. The engine has
the capability of increasing its speed with very little lag behind
the throttle position, even under heavy or full load, meaning
that if the throttle is opened half-way at this slow rate or
slower, that the engine will have come up in speed slowly with the
slow opening and will have achieved its maximum sustained speed
for this throttle opening and particular load momentarily after
the throttle movement stops, and will overrun the aforesaid
maximum sustained insignificantly, thereby staying essentially
in phase with the throttle, even under no load conditions. In
the commercial engine application range considered so far, an
approximately twenty to twenty-five second throttle movement
period seems about the optimum for satisfactory governor regula-
tion for a smoothly operating governor and a period as short as
seven or eight seconds causes objectionable oscillations. Of
course, to obtain satisfactory restraint under no load engine
run-up conditions and satisfactory recovery from sudden load
applications, it is desirable to have fast throttle closing upon
sudden acceleration of the engine, and fast throttle opening upon
sudden deceleration. The apparatus of the present invention
provides such capability for both fast and slow throttle movement
through the use of a reference position for the throttle limiting
means, such that throttle movement will be slow under normal
conditions, but may be swift when needed for recovery of control
of a rapidly fluctuating engine speed caused by some factor
-24-
361
external to the governor. To date, the apparatus of the present
invention is the only known solution to this problem for every-
day commercial use, e.g., as for truck and bus engines. Upon
arrival at its reference posltion, assuming that the engine speed
still lies in the A000-4300 RPM range, the carrier stops and
remains in place, moving therefrom only upon detection of engine
speed outside the 4000-4300 RPM range, and only at the above-
mentioned slow speed, whether in open throttle or close throttle
direction.
When the engine speed drops below 4000 RPM, the motor
132 is energized at the slow speed in open throttle direction and
continues in that direction until the carrier contact 128 hits the
limiting contact 120 and halts there, unless in the meantime the
engine speed has risen again to 4000 RPM to cause the motor 132
to be reversed to close throttle direction, or has dropped below
the 3400 RPM precall speed which will cause the carrier 88 to
continue to open throttle direction, but at high speed a~ter
touching the contact 120. If the carrier contact 128 is halted
upon touching the limiting contact 120, it remains there pending
detection of engine speed rising to 4000 RPM to cause close
throttle drive at the slow speed, or engine speed falling below
the 3400 RPM precall speed to cause open throttle drive just as
in the second embodiment; however, the motor 132 will return to
its normal fast speed because the carrier contact 128 is contact-
ing the limiting contact 120.
As a practical matter, on a long steep grade in a
truck engine application, where a considerably open throttle
position is required to maintain the engine at the 4000 RPM
governed speed, after the throttle limiting means has been moved
to the reference position, then the governor will allow the
-25-
5~
throttle to slowly open farther to a poin-t where its average
position ~urnishes just the fuel needed to maintain 4000 RPM with
only minor oscillations thereabout as the throttle is opened and
closed slightly by governor detection of engine speed falling
below 4000 RPM and then rising back to that speed.
The circuitry for obtaining the slow-motor speed in
both directions, and only when the carrier contact 128 is out of
contact with the limiting contact 120, comprises essentially a
suitable resistor R31 placed in the 12 volt common supply connec-
tion to the motor 132 as shown in Fig. 7 in partial schematicdetail. The resistor R31 reduces the voltage across the motor
132 sufficiently to cause it to run at the desirable low speed in
close throttle direction where the force of the load speed
governor spring 142 and throttle apparatus springs must be
overcome, and a second resistor R30 in the open throttle connec-
tion between the transistor Q3 and the motor 132 reduces the
voltage across the motor even farther to compensate for the over-
running ~orce applied by the governor spring 142 and throttle
apparatus springs when the motor runs in throttle opening direc-
tion. A PNP transistor Q7 is connected in parallel with theresistor R31 and is controlled indirectly through additional
circuitry (not shown) associated with the limiting contact 120 by
the condition thereof. When contact 120 is grounded by contact
with the carrier contact 128, the transistor Q7 is caused to be
conductive, the resistor R31 is shunted out of the circuit and
is of no effect, and the motor 132 runs at normal fast speed.
When the carrier contact 128 leaves the limiting contact 120,
leaving it ungrounded, then the transistor Q7 goes non-conducting
and all current to the motor 132 must pass through the resistor
31, so that the motor runs at the desirable slow speed.
-26-
This third, slow speed, embodiment lessens the oscilla-
tions of engine speed, and would be preferable to the first,
alternating circuit, embodiment except that the low motor voltages
required to obtain a sui-tably slow operation of the motor 132
may not provide sufficient starting torque for reliable motor
operation under extreme cold weather conditions. However, gover-
nors 30 according to this third embodiment have worked satis-
factorily in moderate temperature conditions and commercially
demonstrate the advantages of slow speed operation of the motor
132.
Control of the motor 132 by the load speed governor 86
(through movement of the carrier 88 and its open throttle and
close throttle contacts 134 and 136 respectively, by action of
the flyball mechanism 146 to move the grounding contacts 138) is
the same as that disclosed in my aforementioned prior patent
application, whereby the load speed governor can overridingly run
the moto~ 132 in close throttle direction in response to suit-
ably high load speed at any time, and the engine speed governor
90 can do likewise at any time in response to a suitably high
engine speed, but the load speed governor can only run the motor
132 in open throttle direction in response to a suitably low
load speed when the engine speed governor 90 is also calling
concurrently for the motor to operate in that direction in
response to a suitably low engine speed by making the transistor
Q3 conductive, and vice-versa.
The present invention has been described in detail
above for purposes of illustration only and is not intended to
be limited by this description or otherwise to exclude any
variation or equivalent arrangement that would be apparent from,
or reasonably suggested by, the foregoing disclosure to the
skill of the art, such as the substitution of vacuum or mechanical
-27-
or other actuators, or the electrically driven lead screw dis-
closed herein, the substitution of centrifugal or magnetic or other
engine speed responsive means for the electronic module disclosed
herein, or the substitution of magnetic or electronic or other
load speed responsive means for the fly ball mechanism disclosed
herein. I.e., the scope of the present invention is to be
determined by the scope of the appended claims.
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